Commit Graph

23358 Commits

Author SHA1 Message Date
Will Deacon
c9bbdd4830 perf/core: Don't pass PERF_EF_START to the PMU ->start callback
PERF_EF_START is a flag to indicate to the PMU ->add() callback that, as
well as claiming the PMU resources required by the event being added,
it should also start the PMU.

Passing this flag to the ->start() callback doesn't make sense, because
->start() always tries to start the PMU. Remove it.

Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: mark.rutland@arm.com
Link: http://lkml.kernel.org/r/1471257765-29662-1-git-send-email-will.deacon@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-09-05 13:19:18 +02:00
Ingo Molnar
2cc538412a Merge branch 'perf/urgent' into perf/core, to pick up fixed and resolve conflicts
Conflicts:
	kernel/events/core.c

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-09-05 12:09:59 +02:00
Balbir Singh
135e8c9250 sched/core: Fix a race between try_to_wake_up() and a woken up task
The origin of the issue I've seen is related to
a missing memory barrier between check for task->state and
the check for task->on_rq.

The task being woken up is already awake from a schedule()
and is doing the following:

	do {
		schedule()
		set_current_state(TASK_(UN)INTERRUPTIBLE);
	} while (!cond);

The waker, actually gets stuck doing the following in
try_to_wake_up():

	while (p->on_cpu)
		cpu_relax();

Analysis:

The instance I've seen involves the following race:

 CPU1					CPU2

 while () {
   if (cond)
     break;
   do {
     schedule();
     set_current_state(TASK_UN..)
   } while (!cond);
					wakeup_routine()
					  spin_lock_irqsave(wait_lock)
   raw_spin_lock_irqsave(wait_lock)	  wake_up_process()
 }					  try_to_wake_up()
 set_current_state(TASK_RUNNING);	  ..
 list_del(&waiter.list);

CPU2 wakes up CPU1, but before it can get the wait_lock and set
current state to TASK_RUNNING the following occurs:

 CPU3
 wakeup_routine()
 raw_spin_lock_irqsave(wait_lock)
 if (!list_empty)
   wake_up_process()
   try_to_wake_up()
   raw_spin_lock_irqsave(p->pi_lock)
   ..
   if (p->on_rq && ttwu_wakeup())
   ..
   while (p->on_cpu)
     cpu_relax()
   ..

CPU3 tries to wake up the task on CPU1 again since it finds
it on the wait_queue, CPU1 is spinning on wait_lock, but immediately
after CPU2, CPU3 got it.

CPU3 checks the state of p on CPU1, it is TASK_UNINTERRUPTIBLE and
the task is spinning on the wait_lock. Interestingly since p->on_rq
is checked under pi_lock, I've noticed that try_to_wake_up() finds
p->on_rq to be 0. This was the most confusing bit of the analysis,
but p->on_rq is changed under runqueue lock, rq_lock, the p->on_rq
check is not reliable without this fix IMHO. The race is visible
(based on the analysis) only when ttwu_queue() does a remote wakeup
via ttwu_queue_remote. In which case the p->on_rq change is not
done uder the pi_lock.

The result is that after a while the entire system locks up on
the raw_spin_irqlock_save(wait_lock) and the holder spins infintely

Reproduction of the issue:

The issue can be reproduced after a long run on my system with 80
threads and having to tweak available memory to very low and running
memory stress-ng mmapfork test. It usually takes a long time to
reproduce. I am trying to work on a test case that can reproduce
the issue faster, but thats work in progress. I am still testing the
changes on my still in a loop and the tests seem OK thus far.

Big thanks to Benjamin and Nick for helping debug this as well.
Ben helped catch the missing barrier, Nick caught every missing
bit in my theory.

Signed-off-by: Balbir Singh <bsingharora@gmail.com>
[ Updated comment to clarify matching barriers. Many
  architectures do not have a full barrier in switch_to()
  so that cannot be relied upon. ]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Alexey Kardashevskiy <aik@ozlabs.ru>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nicholas Piggin <nicholas.piggin@gmail.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/e02cce7b-d9ca-1ad0-7a61-ea97c7582b37@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-09-05 11:57:53 +02:00
Peter Zijlstra
5876314875 perf/core: Remove WARN from perf_event_read()
This effectively reverts commit:

  71e7bc2bab ("perf/core: Check return value of the perf_event_read() IPI")

... and puts in a comment explaining why we ignore the return value.

Reported-by: Vegard Nossum <vegard.nossum@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: David Carrillo-Cisneros <davidcc@google.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 71e7bc2bab ("perf/core: Check return value of the perf_event_read() IPI")
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-09-05 11:55:00 +02:00
Linus Torvalds
1c3333600b Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer fixes from Thomas Gleixner:
 "Two fixlet from the timers departement:

   - A fix for scheduler stalls in the tick idle code affecting
     NOHZ_FULL kernels

   - A trivial compile fix"

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  tick/nohz: Fix softlockup on scheduler stalls in kvm guest
  clocksource/drivers/atmel-pit: Fix compilation error
2016-09-04 08:43:45 -07:00
Lianwei Wang
01b4115906 cpu/hotplug: Handle unbalanced hotplug enable/disable
When cpu_hotplug_enable() is called unbalanced w/o a preceeding
cpu_hotplug_disable() the code emits a warning, but happily decrements the
disabled counter. This causes the next operations to malfunction.

Prevent the decrement and just emit a warning.

Signed-off-by: Lianwei Wang <lianwei.wang@gmail.com>
Cc: peterz@infradead.org
Cc: linux-pm@vger.kernel.org
Cc: oleg@redhat.com
Link: http://lkml.kernel.org/r/1465541008-12476-1-git-send-email-lianwei.wang@gmail.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-09-02 20:37:17 +02:00
Sebastian Frias
f88eecfe2f genirq/generic_chip: Verify irqs_per_chip <= 32
Most (if not all) code here implicitly assumes that the maximum number of
IRQs per chip will be 32, and thus uses 'u32' or 'unsigned long' for many
tasks (for example "struct irq_data" declares its 'mask' field as 'u32',
and "struct irq_chip_generic" declares its 'installed' field as 'unsigned
long')

However, there is no check to verify that irqs_per_chip is <= 32.  Hence,
calling irq_alloc_domain_generic_chips() with a bigger value will result in
unexpected results.

Provide a wrapper with a MAYBE_BUILD_BUG_ON(nrirqs >= 32) to catch such
cases.

[ tglx: Reduced changelog to the essential information ]

Signed-off-by: Sebastian Frias <sf84@laposte.net>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Mason <slash.tmp@free.fr>
Cc: Jason Cooper <jason@lakedaemon.net>
Link: http://lkml.kernel.org/r/57B31D94.5040701@laposte.net
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-09-02 20:20:59 +02:00
Thomas Gleixner
cf392d10b6 cpu/hotplug: Add multi instance support
This patch adds the ability for a given state to have multiple
instances. Until now all states have a single instance and the startup /
teardown callback use global variables.
A few drivers need to perform a the same callbacks on multiple
"instances". Currently we have three drivers in tree which all have a
global list which they iterate over. With multi instance they support
don't need their private list and the functionality has been moved into
core code. Plus we hold the hotplug lock in core so no cpus comes/goes
while instances are registered and we do rollback in error case :)

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: rt@linutronix.de
Link: http://lkml.kernel.org/r/1471024183-12666-3-git-send-email-bigeasy@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-09-02 20:05:05 +02:00
Thomas Gleixner
a724632ca0 cpu/hotplug: Rework callback invocation logic
This is preparation for the following patch.
This rework here changes the arguments of cpuhp_invoke_callback(). It
passes now `state' and whether `startup' or `teardown' callback should
be invoked. The callback then is looked up by the function.

The following is a clanup of callers:
- cpuhp_issue_call() has one argument less
- struct cpuhp_cpu_state (which is used by the hotplug thread) gets also
  its callback removed. The decision if it is a single callback
  invocation moved to the `single' variable. Also a `bringup' variable
  has been added to distinguish between startup and teardown callback.
- take_cpu_down() needs to start one step earlier. We always get here
  via CPUHP_TEARDOWN_CPU callback. Before that change cpuhp_ap_states +
  CPUHP_TEARDOWN_CPU pointed to an empty entry because TEARDOWN is saved
  in bp_states for this reason. Now that we use cpuhp_get_step() to
  lookup the state we must explicitly skip it in order not to invoke it
  twice.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: rt@linutronix.de
Link: http://lkml.kernel.org/r/1471024183-12666-2-git-send-email-bigeasy@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-09-02 20:05:05 +02:00
Alexei Starovoitov
aa6a5f3cb2 perf, bpf: add perf events core support for BPF_PROG_TYPE_PERF_EVENT programs
Allow attaching BPF_PROG_TYPE_PERF_EVENT programs to sw and hw perf events
via overflow_handler mechanism.
When program is attached the overflow_handlers become stacked.
The program acts as a filter.
Returning zero from the program means that the normal perf_event_output handler
will not be called and sampling event won't be stored in the ring buffer.

The overflow_handler_context==NULL is an additional safety check
to make sure programs are not attached to hw breakpoints and watchdog
in case other checks (that prevent that now anyway) get accidentally
relaxed in the future.

The program refcnt is incremented in case perf_events are inhereted
when target task is forked.
Similar to kprobe and tracepoint programs there is no ioctl to
detach the program or swap already attached program. The user space
expected to close(perf_event_fd) like it does right now for kprobe+bpf.
That restriction simplifies the code quite a bit.

The invocation of overflow_handler in __perf_event_overflow() is now
done via READ_ONCE, since that pointer can be replaced when the program
is attached while perf_event itself could have been active already.
There is no need to do similar treatment for event->prog, since it's
assigned only once before it's accessed.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-09-02 10:46:44 -07:00
Alexei Starovoitov
fdc15d388d bpf: perf_event progs should only use preallocated maps
Make sure that BPF_PROG_TYPE_PERF_EVENT programs only use
preallocated hash maps, since doing memory allocation
in overflow_handler can crash depending on where nmi got triggered.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-09-02 10:46:44 -07:00
Alexei Starovoitov
0515e5999a bpf: introduce BPF_PROG_TYPE_PERF_EVENT program type
Introduce BPF_PROG_TYPE_PERF_EVENT programs that can be attached to
HW and SW perf events (PERF_TYPE_HARDWARE and PERF_TYPE_SOFTWARE
correspondingly in uapi/linux/perf_event.h)

The program visible context meta structure is
struct bpf_perf_event_data {
    struct pt_regs regs;
     __u64 sample_period;
};
which is accessible directly from the program:
int bpf_prog(struct bpf_perf_event_data *ctx)
{
  ... ctx->sample_period ...
  ... ctx->regs.ip ...
}

The bpf verifier rewrites the accesses into kernel internal
struct bpf_perf_event_data_kern which allows changing
struct perf_sample_data without affecting bpf programs.
New fields can be added to the end of struct bpf_perf_event_data
in the future.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-09-02 10:46:44 -07:00
Alexei Starovoitov
ea2e7ce5d0 bpf: support 8-byte metafield access
The verifier supported only 4-byte metafields in
struct __sk_buff and struct xdp_md. The metafields in upcoming
struct bpf_perf_event are 8-byte to match register width in struct pt_regs.
Teach verifier to recognize 8-byte metafield access.
The patch doesn't affect safety of sockets and xdp programs.
They check for 4-byte only ctx access before these conditions are hit.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-09-02 10:46:44 -07:00
Steven Rostedt (Red Hat)
7b2c862501 tracing: Add NMI tracing in hwlat detector
As NMIs can also cause latency when interrupts are disabled, the hwlat
detectory has no way to know if the latency it detects is from an NMI or an
SMI or some other hardware glitch.

As ftrace_nmi_enter/exit() funtions are no longer used (except for sh, which
isn't supported anymore), I converted those to "arch_ftrace_nmi_enter/exit"
and use ftrace_nmi_enter/exit() to check if hwlat detector is tracing or
not, and if so, it calls into the hwlat utility.

Since the hwlat detector only has a single kthread that is spinning with
interrupts disabled, it marks what CPU it is on, and if the NMI callback
happens on that CPU, it records the time spent in that NMI. This is added to
the output that is generated by the hwlat detector as:

 #3     inner/outer(us):    9/9     ts:1470836488.206734548
 #4     inner/outer(us):    0/8     ts:1470836497.140808588
 #5     inner/outer(us):    0/6     ts:1470836499.140825168 nmi-total:5 nmi-count:1
 #6     inner/outer(us):    9/9     ts:1470836501.140841748

All time is still tracked in microseconds.

The NMI information is only shown when an NMI occurred during the sample.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-09-02 12:47:55 -04:00
Steven Rostedt (Red Hat)
0330f7aa8e tracing: Have hwlat trace migrate across tracing_cpumask CPUs
Instead of having the hwlat detector thread stay on one CPU, have it migrate
across all the CPUs specified by tracing_cpumask. If the user modifies the
thread's CPU affinity, the migration will stop until the next instance that
the tracer is instantiated. The migration happens at the end of each window
(period).

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-09-02 12:47:54 -04:00
Steven Rostedt (Red Hat)
e7c15cd8a1 tracing: Added hardware latency tracer
The hardware latency tracer has been in the PREEMPT_RT patch for some time.
It is used to detect possible SMIs or any other hardware interruptions that
the kernel is unaware of. Note, NMIs may also be detected, but that may be
good to note as well.

The logic is pretty simple. It simply creates a thread that spins on a
single CPU for a specified amount of time (width) within a periodic window
(window). These numbers may be adjusted by their cooresponding names in

   /sys/kernel/tracing/hwlat_detector/

The defaults are window = 1000000 us (1 second)
                 width  =  500000 us (1/2 second)

The loop consists of:

	t1 = trace_clock_local();
	t2 = trace_clock_local();

Where trace_clock_local() is a variant of sched_clock().

The difference of t2 - t1 is recorded as the "inner" timestamp and also the
timestamp  t1 - prev_t2 is recorded as the "outer" timestamp. If either of
these differences are greater than the time denoted in
/sys/kernel/tracing/tracing_thresh then it records the event.

When this tracer is started, and tracing_thresh is zero, it changes to the
default threshold of 10 us.

The hwlat tracer in the PREEMPT_RT patch was originally written by
Jon Masters. I have modified it quite a bit and turned it into a
tracer.

Based-on-code-by: Jon Masters <jcm@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-09-02 12:47:51 -04:00
Sebastian Frias
0c228919e0 irqdomain: Mask irq type in irq_domain_xlate_onetwocell()
According to the xlate() callback definition, the 'out_type' parameter
needs to be the "linux irq type".

A mask for such bits exists, IRQ_TYPE_SENSE_MASK, which is correctly
applied in irq_domain_xlate_twocell()

So use it for irq_domain_xlate_onetwocell() as well.

Signed-off-by: Sebastian Frias <sf84@laposte.net>
Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Mason <slash.tmp@free.fr>
Cc: Jason Cooper <jason@lakedaemon.net>
Link: http://lkml.kernel.org/r/57A05F5D.103@laposte.net
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-09-02 18:06:50 +02:00
Sebastian Frias
ee26c013cd genirq/generic_chip: Add irq_unmap callback
Without this patch irq_domain_disassociate() cannot properly release the
interrupt. In fact, irq_map_generic_chip() checks a bit on 'gc->installed'
but said bit is never cleared, only set.

Commit 088f40b7b0 ("genirq: Generic chip: Add linear irq domain support")
added irq_map_generic_chip() function and also stated "This lacks a removal
function for now".

This commit provides an implementation of an unmap function that can be
called by irq_domain_disassociate().

[ tglx: Made the function static and removed the export as we have neither
  	a prototype nor a modular user. ]

Fixes: 088f40b7b0 ("genirq: Generic chip: Add linear irq domain support")
Signed-off-by: Sebastian Frias <sf84@laposte.net>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Mason <slash.tmp@free.fr>
Cc: Jason Cooper <jason@lakedaemon.net>
Link: http://lkml.kernel.org/r/579F5C5A.2070507@laposte.net
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-09-02 18:06:49 +02:00
Sebastian Frias
f0c450eaa3 genirq/generic_chip: Get rid of code duplication
irq_map_generic_chip() contains about the same code as
irq_get_domain_generic_chip() except for the return values.

Split out the irq_get_domain_generic_chip() implementation so it can be
reused.

[ tglx: Removed the extra churn in irq_get_domain_generic_chip() callers
  	and massaged changelog ]

Signed-off-by: Sebastian Frias <sf84@laposte.net>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Mason <slash.tmp@free.fr>
Cc: Jason Cooper <jason@lakedaemon.net>
Link: http://lkml.kernel.org/r/579F5C69.8070006@laposte.net
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-09-02 18:06:49 +02:00
Thomas Gleixner
48e0fba842 genirq: Remove export of irq_map_generic_chip()
No module users.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-09-02 18:06:49 +02:00
Thomas Gleixner
fc590c22f9 genirq: Robustify handle_percpu_devid_irq()
The percpu_devid handler is not robust against spurious interrupts. If a
spurious interrupt happens and no action is installed then the handler
crashes with a NULL pointer dereference.

Add a sanity check for this and log the wreckage once in dmesg.

Reported-by: Majun <majun258@huawei.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: guohanjun@huawei.com
Cc: dingtianhong@huawei.com
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1609021436160.5647@nanos
2016-09-02 18:06:49 +02:00
Wanpeng Li
08d0725992 tick/nohz: Fix softlockup on scheduler stalls in kvm guest
tick_nohz_start_idle() is prevented to be called if the idle tick can't 
be stopped since commit 1f3b0f8243 ("tick/nohz: Optimize nohz idle 
enter"). As a result, after suspend/resume the host machine, full dynticks 
kvm guest will softlockup:

 NMI watchdog: BUG: soft lockup - CPU#0 stuck for 26s! [swapper/0:0]
 Call Trace:
  default_idle+0x31/0x1a0
  arch_cpu_idle+0xf/0x20
  default_idle_call+0x2a/0x50
  cpu_startup_entry+0x39b/0x4d0
  rest_init+0x138/0x140
  ? rest_init+0x5/0x140
  start_kernel+0x4c1/0x4ce
  ? set_init_arg+0x55/0x55
  ? early_idt_handler_array+0x120/0x120
  x86_64_start_reservations+0x24/0x26
  x86_64_start_kernel+0x142/0x14f

In addition, cat /proc/stat | grep cpu in guest or host:

cpu  398 16 5049 15754 5490 0 1 46 0 0
cpu0 206 5 450 0 0 0 1 14 0 0
cpu1 81 0 3937 3149 1514 0 0 9 0 0
cpu2 45 6 332 6052 2243 0 0 11 0 0
cpu3 65 2 328 6552 1732 0 0 11 0 0

The idle and iowait states are weird 0 for cpu0(housekeeping). 

The bug is present in both guest and host kernels, and they both have 
cpu0's idle and iowait states issue, however, host kernel's suspend/resume 
path etc will touch watchdog to avoid the softlockup.

- The watchdog will not be touched in tick_nohz_stop_idle path (need be 
  touched since the scheduler stall is expected) if idle_active flags are 
  not detected.
- The idle and iowait states will not be accounted when exit idle loop 
  (resched or interrupt) if idle start time and idle_active flags are 
  not set. 

This patch fixes it by reverting commit 1f3b0f8243 since can't stop 
idle tick doesn't mean can't be idle.

Fixes: 1f3b0f8243 ("tick/nohz: Optimize nohz idle enter")
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Cc: Sanjeev Yadav<sanjeev.yadav@spreadtrum.com>
Cc: Gaurav Jindal<gaurav.jindal@spreadtrum.com>
Cc: stable@vger.kernel.org
Cc: kvm@vger.kernel.org
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Link: http://lkml.kernel.org/r/1472798303-4154-1-git-send-email-wanpeng.li@hotmail.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-09-02 10:25:40 +02:00
Linus Torvalds
b9677faf45 Merge branch 'akpm' (patches from Andrew)
Merge fixes from Andrew Morton:
 "14 fixes"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  rapidio/tsi721: fix incorrect detection of address translation condition
  rapidio/documentation/mport_cdev: add missing parameter description
  kernel/fork: fix CLONE_CHILD_CLEARTID regression in nscd
  MAINTAINERS: Vladimir has moved
  mm, mempolicy: task->mempolicy must be NULL before dropping final reference
  printk/nmi: avoid direct printk()-s from __printk_nmi_flush()
  treewide: remove references to the now unnecessary DEFINE_PCI_DEVICE_TABLE
  drivers/scsi/wd719x.c: remove last declaration using DEFINE_PCI_DEVICE_TABLE
  mm, vmscan: only allocate and reclaim from zones with pages managed by the buddy allocator
  lib/test_hash.c: fix warning in preprocessor symbol evaluation
  lib/test_hash.c: fix warning in two-dimensional array init
  kconfig: tinyconfig: provide whole choice blocks to avoid warnings
  kexec: fix double-free when failing to relocate the purgatory
  mm, oom: prevent premature OOM killer invocation for high order request
2016-09-01 18:23:22 -07:00
Michal Hocko
735f2770a7 kernel/fork: fix CLONE_CHILD_CLEARTID regression in nscd
Commit fec1d01152 ("[PATCH] Disable CLONE_CHILD_CLEARTID for abnormal
exit") has caused a subtle regression in nscd which uses
CLONE_CHILD_CLEARTID to clear the nscd_certainly_running flag in the
shared databases, so that the clients are notified when nscd is
restarted.  Now, when nscd uses a non-persistent database, clients that
have it mapped keep thinking the database is being updated by nscd, when
in fact nscd has created a new (anonymous) one (for non-persistent
databases it uses an unlinked file as backend).

The original proposal for the CLONE_CHILD_CLEARTID change claimed
(https://lkml.org/lkml/2006/10/25/233):

: The NPTL library uses the CLONE_CHILD_CLEARTID flag on clone() syscalls
: on behalf of pthread_create() library calls.  This feature is used to
: request that the kernel clear the thread-id in user space (at an address
: provided in the syscall) when the thread disassociates itself from the
: address space, which is done in mm_release().
:
: Unfortunately, when a multi-threaded process incurs a core dump (such as
: from a SIGSEGV), the core-dumping thread sends SIGKILL signals to all of
: the other threads, which then proceed to clear their user-space tids
: before synchronizing in exit_mm() with the start of core dumping.  This
: misrepresents the state of process's address space at the time of the
: SIGSEGV and makes it more difficult for someone to debug NPTL and glibc
: problems (misleading him/her to conclude that the threads had gone away
: before the fault).
:
: The fix below is to simply avoid the CLONE_CHILD_CLEARTID action if a
: core dump has been initiated.

The resulting patch from Roland (https://lkml.org/lkml/2006/10/26/269)
seems to have a larger scope than the original patch asked for.  It
seems that limitting the scope of the check to core dumping should work
for SIGSEGV issue describe above.

[Changelog partly based on Andreas' description]
Fixes: fec1d01152 ("[PATCH] Disable CLONE_CHILD_CLEARTID for abnormal exit")
Link: http://lkml.kernel.org/r/1471968749-26173-1-git-send-email-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Tested-by: William Preston <wpreston@suse.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: Roland McGrath <roland@hack.frob.com>
Cc: Andreas Schwab <schwab@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-09-01 17:52:02 -07:00
David Rientjes
c11600e4fe mm, mempolicy: task->mempolicy must be NULL before dropping final reference
KASAN allocates memory from the page allocator as part of
kmem_cache_free(), and that can reference current->mempolicy through any
number of allocation functions.  It needs to be NULL'd out before the
final reference is dropped to prevent a use-after-free bug:

	BUG: KASAN: use-after-free in alloc_pages_current+0x363/0x370 at addr ffff88010b48102c
	CPU: 0 PID: 15425 Comm: trinity-c2 Not tainted 4.8.0-rc2+ #140
	...
	Call Trace:
		dump_stack
		kasan_object_err
		kasan_report_error
		__asan_report_load2_noabort
		alloc_pages_current	<-- use after free
		depot_save_stack
		save_stack
		kasan_slab_free
		kmem_cache_free
		__mpol_put		<-- free
		do_exit

This patch sets current->mempolicy to NULL before dropping the final
reference.

Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1608301442180.63329@chino.kir.corp.google.com
Fixes: cd11016e5f ("mm, kasan: stackdepot implementation. Enable stackdepot for SLAB")
Signed-off-by: David Rientjes <rientjes@google.com>
Reported-by: Vegard Nossum <vegard.nossum@oracle.com>
Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: <stable@vger.kernel.org>	[4.6+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-09-01 17:52:01 -07:00
Sergey Senozhatsky
19feeff18b printk/nmi: avoid direct printk()-s from __printk_nmi_flush()
__printk_nmi_flush() can be called from nmi_panic(), therefore it has to
test whether it's executed in NMI context and thus must route the
messages through deferred printk() or via direct printk().

This is to avoid potential deadlocks, as described in commit
cf9b1106c8 ("printk/nmi: flush NMI messages on the system panic").

However there remain two places where __printk_nmi_flush() does
unconditional direct printk() calls:

 - pr_err("printk_nmi_flush: internal error ...")
 - pr_cont("\n")

Factor out print_nmi_seq_line() parts into a new printk_nmi_flush_line()
function, which takes care of in_nmi(), and use it in
__printk_nmi_flush() for printing and error-reporting.

Link: http://lkml.kernel.org/r/20160830161354.581-1-sergey.senozhatsky@gmail.com
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-09-01 17:52:01 -07:00
Arnd Bergmann
236dec0510 kconfig: tinyconfig: provide whole choice blocks to avoid warnings
Using "make tinyconfig" produces a couple of annoying warnings that show
up for build test machines all the time:

    .config:966:warning: override: NOHIGHMEM changes choice state
    .config:965:warning: override: SLOB changes choice state
    .config:963:warning: override: KERNEL_XZ changes choice state
    .config:962:warning: override: CC_OPTIMIZE_FOR_SIZE changes choice state
    .config:933:warning: override: SLOB changes choice state
    .config:930:warning: override: CC_OPTIMIZE_FOR_SIZE changes choice state
    .config:870:warning: override: SLOB changes choice state
    .config:868:warning: override: KERNEL_XZ changes choice state
    .config:867:warning: override: CC_OPTIMIZE_FOR_SIZE changes choice state

I've made a previous attempt at fixing them and we discussed a number of
alternatives.

I tried changing the Makefile to use "merge_config.sh -n
$(fragment-list)" but couldn't get that to work properly.

This is yet another approach, based on the observation that we do want
to see a warning for conflicting 'choice' options, and that we can
simply make them non-conflicting by listing all other options as
disabled.  This is a trivial patch that we can apply independent of
plans for other changes.

Link: http://lkml.kernel.org/r/20160829214952.1334674-2-arnd@arndb.de
Link: https://storage.kernelci.org/mainline/v4.7-rc6/x86-tinyconfig/build.log
https://patchwork.kernel.org/patch/9212749/
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Reviewed-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-09-01 17:52:01 -07:00
Thiago Jung Bauermann
070c43eea5 kexec: fix double-free when failing to relocate the purgatory
If kexec_apply_relocations fails, kexec_load_purgatory frees pi->sechdrs
and pi->purgatory_buf.  This is redundant, because in case of error
kimage_file_prepare_segments calls kimage_file_post_load_cleanup, which
will also free those buffers.

This causes two warnings like the following, one for pi->sechdrs and the
other for pi->purgatory_buf:

  kexec-bzImage64: Loading purgatory failed
  ------------[ cut here ]------------
  WARNING: CPU: 1 PID: 2119 at mm/vmalloc.c:1490 __vunmap+0xc1/0xd0
  Trying to vfree() nonexistent vm area (ffffc90000e91000)
  Modules linked in:
  CPU: 1 PID: 2119 Comm: kexec Not tainted 4.8.0-rc3+ #5
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
  Call Trace:
    dump_stack+0x4d/0x65
    __warn+0xcb/0xf0
    warn_slowpath_fmt+0x4f/0x60
    ? find_vmap_area+0x19/0x70
    ? kimage_file_post_load_cleanup+0x47/0xb0
    __vunmap+0xc1/0xd0
    vfree+0x2e/0x70
    kimage_file_post_load_cleanup+0x5e/0xb0
    SyS_kexec_file_load+0x448/0x680
    ? putname+0x54/0x60
    ? do_sys_open+0x190/0x1f0
    entry_SYSCALL_64_fastpath+0x13/0x8f
  ---[ end trace 158bb74f5950ca2b ]---

Fix by setting pi->sechdrs an pi->purgatory_buf to NULL, since vfree
won't try to free a NULL pointer.

Link: http://lkml.kernel.org/r/1472083546-23683-1-git-send-email-bauerman@linux.vnet.ibm.com
Signed-off-by: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
Acked-by: Baoquan He <bhe@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-09-01 17:52:01 -07:00
Linus Torvalds
511a8cdb65 Merge branch 'stable-4.8' of git://git.infradead.org/users/pcmoore/audit
Pull audit fixes from Paul Moore:
 "Two small patches to fix some bugs with the audit-by-executable
  functionality we introduced back in v4.3 (both patches are marked
  for the stable folks)"

* 'stable-4.8' of git://git.infradead.org/users/pcmoore/audit:
  audit: fix exe_file access in audit_exe_compare
  mm: introduce get_task_exe_file
2016-09-01 15:55:56 -07:00
Thomas Gleixner
0cb7bf61b1 Merge branch 'linus' into smp/hotplug
Apply upstream changes to avoid conflicts with pending patches.
2016-09-01 18:33:46 +02:00
Namhyung Kim
8861dd303c ftrace: Access ret_stack->subtime only in the function profiler
The subtime is used only for function profiler with function graph
tracer enabled.  Move the definition of subtime under
CONFIG_FUNCTION_PROFILER to reduce the memory usage.  Also move the
initialization of subtime into the graph entry callback.

Link: http://lkml.kernel.org/r/20160831025529.24018-1-namhyung@kernel.org

Cc: Ingo Molnar <mingo@kernel.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-09-01 12:19:40 -04:00
Namhyung Kim
613dccdf68 function_graph: Handle TRACE_BPUTS in print_graph_comment
It missed to handle TRACE_BPUTS so messages recorded by trace_bputs()
will be shown with symbol info unnecessarily.

You can see it with the trace_printk sample code:

  # cd /sys/kernel/tracing/
  # echo sys_sync > set_graph_function
  # echo 1 > options/sym-offset
  # echo function_graph > current_tracer

Note that the sys_sync filter was there to prevent recording other
functions and the sym-offset option was needed since the first message
was called from a module init function so kallsyms doesn't have the
symbol and omitted in the output.

  # cd ~/build/kernel
  # insmod samples/trace_printk/trace-printk.ko

  # cd -
  # head trace

Before:

  # tracer: function_graph
  #
  # CPU  DURATION                  FUNCTION CALLS
  # |     |   |                     |   |   |   |
   1)               |  /* 0xffffffffa0002000: This is a static string that will use trace_bputs */
   1)               |  /* This is a dynamic string that will use trace_puts */
   1)               |  /* trace_printk_irq_work+0x5/0x7b [trace_printk]: (irq) This is a static string that will use trace_bputs */
   1)               |  /* (irq) This is a dynamic string that will use trace_puts */
   1)               |  /* (irq) This is a static string that will use trace_bprintk() */
   1)               |  /* (irq) This is a dynamic string that will use trace_printk */

After:

  # tracer: function_graph
  #
  # CPU  DURATION                  FUNCTION CALLS
  # |     |   |                     |   |   |   |
   1)               |  /* This is a static string that will use trace_bputs */
   1)               |  /* This is a dynamic string that will use trace_puts */
   1)               |  /* (irq) This is a static string that will use trace_bputs */
   1)               |  /* (irq) This is a dynamic string that will use trace_puts */
   1)               |  /* (irq) This is a static string that will use trace_bprintk() */
   1)               |  /* (irq) This is a dynamic string that will use trace_printk */

Link: http://lkml.kernel.org/r/20160901024354.13720-1-namhyung@kernel.org

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-09-01 11:19:55 -04:00
Dmitry Safonov
5ba8a4a96f tracing/uprobe: Drop isdigit() check in create_trace_uprobe
It's useless. Before:
  [tracing]# echo 'p:test /a:0x0' >> uprobe_events
  [tracing]# echo 'p:test a:0x0' >> uprobe_events
  -bash: echo: write error: No such file or directory
  [tracing]# echo 'p:test 1:0x0' >> uprobe_events
  -bash: echo: write error: Invalid argument

After:
  [tracing]# echo 'p:test 1:0x0' >> uprobe_events
  -bash: echo: write error: No such file or directory

Link: http://lkml.kernel.org/r/20160825152110.25663-3-dsafonov@virtuozzo.com

Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Dmitry Safonov <dsafonov@virtuozzo.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-09-01 11:18:09 -04:00
Steve Muckle
8314bc83f6 cpufreq / sched: ignore SMT when determining max cpu capacity
PELT does not consider SMT when scaling its utilization values via
arch_scale_cpu_capacity(). The value in rq->cpu_capacity_orig does
take SMT into consideration though and therefore may be smaller than
the utilization reported by PELT.

On an Intel i7-3630QM for example rq->cpu_capacity_orig is 589 but
util_avg scales up to 1024. This means that a 50% utilized CPU will show
up in schedutil as ~86% busy.

Fix this by using the same CPU scaling value in schedutil as that which
is used by PELT.

Signed-off-by: Steve Muckle <smuckle@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2016-09-01 00:32:57 +02:00
Vegard Nossum
979515c564 time: Avoid undefined behaviour in ktime_add_safe()
I ran into this:

    ================================================================================
    UBSAN: Undefined behaviour in kernel/time/hrtimer.c:310:16
    signed integer overflow:
    9223372036854775807 + 50000 cannot be represented in type 'long long int'
    CPU: 2 PID: 4798 Comm: trinity-c2 Not tainted 4.8.0-rc1+ #91
    Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.9.3-0-ge2fc41e-prebuilt.qemu-project.org 04/01/2014
     0000000000000000 ffff88010ce6fb88 ffffffff82344740 0000000041b58ab3
     ffffffff84f97a20 ffffffff82344694 ffff88010ce6fbb0 ffff88010ce6fb60
     000000000000c350 ffff88010ce6f968 dffffc0000000000 ffffffff857bc320
    Call Trace:
     [<ffffffff82344740>] dump_stack+0xac/0xfc
     [<ffffffff82344694>] ? _atomic_dec_and_lock+0xc4/0xc4
     [<ffffffff8242df78>] ubsan_epilogue+0xd/0x8a
     [<ffffffff8242e6b4>] handle_overflow+0x202/0x23d
     [<ffffffff8242e4b2>] ? val_to_string.constprop.6+0x11e/0x11e
     [<ffffffff8236df71>] ? timerqueue_add+0x151/0x410
     [<ffffffff81485c48>] ? hrtimer_start_range_ns+0x3b8/0x1380
     [<ffffffff81795631>] ? memset+0x31/0x40
     [<ffffffff8242e6fd>] __ubsan_handle_add_overflow+0xe/0x10
     [<ffffffff81488ac9>] hrtimer_nanosleep+0x5d9/0x790
     [<ffffffff814884f0>] ? hrtimer_init_sleeper+0x80/0x80
     [<ffffffff813a9ffb>] ? __might_sleep+0x5b/0x260
     [<ffffffff8148be10>] common_nsleep+0x20/0x30
     [<ffffffff814906c7>] SyS_clock_nanosleep+0x197/0x210
     [<ffffffff81490530>] ? SyS_clock_getres+0x150/0x150
     [<ffffffff823c7113>] ? __this_cpu_preempt_check+0x13/0x20
     [<ffffffff8162ef60>] ? __context_tracking_exit.part.3+0x30/0x1b0
     [<ffffffff81490530>] ? SyS_clock_getres+0x150/0x150
     [<ffffffff81007bd3>] do_syscall_64+0x1b3/0x4b0
     [<ffffffff845f85aa>] entry_SYSCALL64_slow_path+0x25/0x25
    ================================================================================

Add a new ktime_add_unsafe() helper which doesn't check for overflow, but
doesn't throw a UBSAN warning when it does overflow either.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
2016-08-31 14:43:36 -07:00
Vegard Nossum
469e857f37 time: Avoid undefined behaviour in timespec64_add_safe()
I ran into this:

    ================================================================================
    UBSAN: Undefined behaviour in kernel/time/time.c:783:2
    signed integer overflow:
    5273 + 9223372036854771711 cannot be represented in type 'long int'
    CPU: 0 PID: 17363 Comm: trinity-c0 Not tainted 4.8.0-rc1+ #88
    Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.9.3-0-ge2fc41e-prebuilt.qemu-project.org
    04/01/2014
     0000000000000000 ffff88011457f8f0 ffffffff82344f50 0000000041b58ab3
     ffffffff84f98080 ffffffff82344ea4 ffff88011457f918 ffff88011457f8c8
     ffff88011457f8e0 7fffffffffffefff ffff88011457f6d8 dffffc0000000000
    Call Trace:
     [<ffffffff82344f50>] dump_stack+0xac/0xfc
     [<ffffffff82344ea4>] ? _atomic_dec_and_lock+0xc4/0xc4
     [<ffffffff8242f4c8>] ubsan_epilogue+0xd/0x8a
     [<ffffffff8242fc04>] handle_overflow+0x202/0x23d
     [<ffffffff8242fa02>] ? val_to_string.constprop.6+0x11e/0x11e
     [<ffffffff823c7837>] ? debug_smp_processor_id+0x17/0x20
     [<ffffffff8131b581>] ? __sigqueue_free.part.13+0x51/0x70
     [<ffffffff8146d4e0>] ? rcu_is_watching+0x110/0x110
     [<ffffffff8242fc4d>] __ubsan_handle_add_overflow+0xe/0x10
     [<ffffffff81476ef8>] timespec64_add_safe+0x298/0x340
     [<ffffffff81476c60>] ? timespec_add_safe+0x330/0x330
     [<ffffffff812f7990>] ? wait_noreap_copyout+0x1d0/0x1d0
     [<ffffffff8184bf18>] poll_select_set_timeout+0xf8/0x170
     [<ffffffff8184be20>] ? poll_schedule_timeout+0x2b0/0x2b0
     [<ffffffff813aa9bb>] ? __might_sleep+0x5b/0x260
     [<ffffffff833c8a87>] __sys_recvmmsg+0x107/0x790
     [<ffffffff833c8980>] ? SyS_recvmsg+0x20/0x20
     [<ffffffff81486378>] ? hrtimer_start_range_ns+0x3b8/0x1380
     [<ffffffff845f8bfb>] ? _raw_spin_unlock_irqrestore+0x3b/0x60
     [<ffffffff8148bcea>] ? do_setitimer+0x39a/0x8e0
     [<ffffffff813aa9bb>] ? __might_sleep+0x5b/0x260
     [<ffffffff833c9110>] ? __sys_recvmmsg+0x790/0x790
     [<ffffffff833c91e9>] SyS_recvmmsg+0xd9/0x160
     [<ffffffff833c9110>] ? __sys_recvmmsg+0x790/0x790
     [<ffffffff823c7853>] ? __this_cpu_preempt_check+0x13/0x20
     [<ffffffff8162f680>] ? __context_tracking_exit.part.3+0x30/0x1b0
     [<ffffffff833c9110>] ? __sys_recvmmsg+0x790/0x790
     [<ffffffff81007bd3>] do_syscall_64+0x1b3/0x4b0
     [<ffffffff845f936a>] entry_SYSCALL64_slow_path+0x25/0x25
    ================================================================================

Line 783 is this:

783         set_normalized_timespec64(&res, lhs.tv_sec + rhs.tv_sec,
784                         lhs.tv_nsec + rhs.tv_nsec);

In other words, since lhs.tv_sec and rhs.tv_sec are both time64_t, this
is a signed addition which will cause undefined behaviour on overflow.

Note that this is not currently a huge concern since the kernel should be
built with -fno-strict-overflow by default, but could be a problem in the
future, a problem with older compilers, or other compilers than gcc.

The easiest way to avoid the overflow is to cast one of the arguments to
unsigned (so the addition will be done using unsigned arithmetic).

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
2016-08-31 14:43:35 -07:00
Ruchi Kandoi
0bf43f15db timekeeping: Prints the amounts of time spent during suspend
In addition to keeping a histogram of suspend times, also
print out the time spent in suspend to dmesg.

This helps to keep track of suspend time while debugging using
kernel logs.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Signed-off-by: Ruchi Kandoi <kandoiruchi@google.com>
[jstultz: Tweaked commit message]
Signed-off-by: John Stultz <john.stultz@linaro.org>
2016-08-31 14:43:34 -07:00
Kyle Walker
36374583f9 clocksource: Defer override invalidation unless clock is unstable
Clocksources don't get the VALID_FOR_HRES flag until they have been
checked by a watchdog. However, when using an override, the
clocksource_select logic will clear the override value if the
clocksource is not marked VALID_FOR_HRES during that inititial check.
When using the boot arguments clocksource=<foo>, this selection can
run before the watchdog, and can cause the override to be incorrectly
cleared.

To address this condition, the override_name is only invalidated for
unstable clocksources. Otherwise, the override is left intact until after
the watchdog has validated the clocksource as stable/unstable.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Kyle Walker <kwalker@redhat.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
2016-08-31 14:43:33 -07:00
Pratyush Patel
b4d90e9f1e hrtimer: Spelling fixes
Fix a minor spelling error.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Signed-off-by: Pratyush Patel <pratyushpatel.1995@gmail.com>
[jstultz: Added commit message]
Signed-off-by: John Stultz <john.stultz@linaro.org>
2016-08-31 14:43:20 -07:00
Mateusz Guzik
5efc244346 audit: fix exe_file access in audit_exe_compare
Prior to the change the function would blindly deference mm, exe_file
and exe_file->f_inode, each of which could have been NULL or freed.

Use get_task_exe_file to safely obtain stable exe_file.

Signed-off-by: Mateusz Guzik <mguzik@redhat.com>
Acked-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Acked-by: Richard Guy Briggs <rgb@redhat.com>
Cc: <stable@vger.kernel.org> # 4.3.x
Signed-off-by: Paul Moore <paul@paul-moore.com>
2016-08-31 16:16:35 -04:00
Mateusz Guzik
cd81a9170e mm: introduce get_task_exe_file
For more convenient access if one has a pointer to the task.

As a minor nit take advantage of the fact that only task lock + rcu are
needed to safely grab ->exe_file. This saves mm refcount dance.

Use the helper in proc_exe_link.

Signed-off-by: Mateusz Guzik <mguzik@redhat.com>
Acked-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Acked-by: Richard Guy Briggs <rgb@redhat.com>
Cc: <stable@vger.kernel.org> # 4.3.x
Signed-off-by: Paul Moore <paul@paul-moore.com>
2016-08-31 16:11:20 -04:00
Eric W. Biederman
537f7ccb39 mntns: Add a limit on the number of mount namespaces.
v2: Fixed the very obvious lack of setting ucounts
    on struct mnt_ns reported by Andrei Vagin, and the kbuild
    test report.

Reported-by: Andrei Vagin <avagin@openvz.org>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2016-08-31 07:28:35 -05:00
Linus Torvalds
61b5ebd6ff Fix fatal signal delivery after ptrace reordering.
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Merge tag 'seccomp-v4.8-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull seccomp fix from Kees Cook:
 "Fix fatal signal delivery after ptrace reordering"

* tag 'seccomp-v4.8-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  seccomp: Fix tracer exit notifications during fatal signals
2016-08-30 16:25:57 -07:00
Kees Cook
485a252a55 seccomp: Fix tracer exit notifications during fatal signals
This fixes a ptrace vs fatal pending signals bug as manifested in
seccomp now that seccomp was reordered to happen after ptrace. The
short version is that seccomp should not attempt to call do_exit()
while fatal signals are pending under a tracer. The existing code was
trying to be as defensively paranoid as possible, but it now ends up
confusing ptrace. Instead, the syscall can just be skipped (which solves
the original concern that the do_exit() was addressing) and normal signal
handling, tracer notification, and process death can happen.

Paraphrasing from the original bug report:

If a tracee task is in a PTRACE_EVENT_SECCOMP trap, or has been resumed
after such a trap but not yet been scheduled, and another task in the
thread-group calls exit_group(), then the tracee task exits without the
ptracer receiving a PTRACE_EVENT_EXIT notification. Test case here:
https://gist.github.com/khuey/3c43ac247c72cef8c956ca73281c9be7

The bug happens because when __seccomp_filter() detects
fatal_signal_pending(), it calls do_exit() without dequeuing the fatal
signal. When do_exit() sends the PTRACE_EVENT_EXIT notification and
that task is descheduled, __schedule() notices that there is a fatal
signal pending and changes its state from TASK_TRACED to TASK_RUNNING.
That prevents the ptracer's waitpid() from returning the ptrace event.
A more detailed analysis is here:
https://github.com/mozilla/rr/issues/1762#issuecomment-237396255.

Reported-by: Robert O'Callahan <robert@ocallahan.org>
Reported-by: Kyle Huey <khuey@kylehuey.com>
Tested-by: Kyle Huey <khuey@kylehuey.com>
Fixes: 93e35efb8d ("x86/ptrace: run seccomp after ptrace")
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: James Morris <james.l.morris@oracle.com>
2016-08-30 16:12:46 -07:00
Paul Moore
fa2bea2f5c audit: consistently record PIDs with task_tgid_nr()
Unfortunately we record PIDs in audit records using a variety of
methods despite the correct way being the use of task_tgid_nr().
This patch converts all of these callers, except for the case of
AUDIT_SET in audit_receive_msg() (see the comment in the code).

Reported-by: Jeff Vander Stoep <jeffv@google.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2016-08-30 17:19:13 -04:00
Linus Torvalds
748e7fc209 Merge branch 'for-4.8-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup fixes from Tejun Heo:
 "Two fixes for cgroup.

   - There still was a hole in enforcing cpuset rules, fixed by Li.

   - The recent switch to global percpu_rwseom for threadgroup locking
     revealed a couple issues in how percpu_rwsem is implemented and
     used by cgroup.  Balbir found that the read locking section was too
     wide unnecessarily including operations which can often depend on
     IOs.  With percpu_rwsem updates (coming through a different tree)
     and reduction of read locking section, all the reported locking
     latency issues, including the android one, are resolved.

  It looks like we can keep global percpu_rwsem locking for now.  If
  there actually are cases which can't be resolved, we can go back to
  more complex per-signal_struct locking"

* 'for-4.8-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  cgroup: reduce read locked section of cgroup_threadgroup_rwsem during fork
  cpuset: make sure new tasks conform to the current config of the cpuset
2016-08-30 09:31:59 -07:00
David S. Miller
6abdd5f593 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
All three conflicts were cases of simple overlapping
changes.

Signed-off-by: David S. Miller <davem@davemloft.net>
2016-08-30 00:54:02 -04:00
Jens Axboe
f72b8792d1 workqueue: add cancel_work()
Like cancel_delayed_work(), but for regular work.

Signed-off-by: Jens Axboe <axboe@fb.com>
Mehed-by: Tejun Heo <tj@kernel.org>
Acked-by: Tejun Heo <tj@kernel.org>
2016-08-29 08:13:21 -06:00
Linus Torvalds
908e373f1c Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf fixes from Thomas Gleixner:
 "A few fixes from the perf departement

   - prevent a imbalanced preemption disable in the events teardown code
   - prevent out of bound acces in perf userspace
   - make perf tools compile with UCLIBC again
   - a fix for the userspace unwinder utility"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/core: Use this_cpu_ptr() when stopping AUX events
  perf evsel: Do not access outside hw cache name arrays
  tools lib: Reinstate strlcpy() header guard with __UCLIBC__
  perf unwind: Use addr_location::addr instead of ip for entries
2016-08-28 10:02:23 -07:00
Linus Torvalds
4340393e5a Merge branch 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull irq fixes from Thomas Gleixner:
 "This lot provides:

   - plug a hotplug race in the new affinity infrastructure
   - a fix for the trigger type of chained interrupts
   - plug a potential memory leak in the core code
   - a few fixes for ARM and MIPS GICs"

* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  irqchip/mips-gic: Implement activate op for device domain
  irqchip/mips-gic: Cleanup chip and handler setup
  genirq/affinity: Use get/put_online_cpus around cpumask operations
  genirq: Fix potential memleak when failing to get irq pm
  irqchip/gicv3-its: Disable the ITS before initializing it
  irqchip/gicv3: Remove disabling redistributor and group1 non-secure interrupts
  irqchip/gic: Allow self-SGIs for SMP on UP configurations
  genirq: Correctly configure the trigger on chained interrupts
2016-08-28 09:52:40 -07:00
Linus Torvalds
037d2405d0 Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer fixes from Thomas Gleixner:
 "A few updates for timers & co:

   - prevent a livelock in the timekeeping code when debugging is
     enabled

   - prevent out of bounds access in the timekeeping debug code

   - various fixes in clocksource drivers

   - a new maintainers entry"

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  clocksource/drivers/sun4i: Clear interrupts after stopping timer in probe function
  drivers/clocksource/pistachio: Fix memory corruption in init
  clocksource/drivers/timer-atmel-pit: Enable mck clock
  clocksource/drivers/pxa: Fix include files for compilation
  MAINTAINERS: Add ARM ARCHITECTED TIMER entry
  timekeeping: Cap array access in timekeeping_debug
  timekeeping: Avoid taking lock in NMI path with CONFIG_DEBUG_TIMEKEEPING
2016-08-28 09:03:05 -07:00
Linus Torvalds
5e608a0270 Merge branch 'akpm' (patches from Andrew)
Merge fixes from Andrew Morton:
 "11 fixes"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  mm: silently skip readahead for DAX inodes
  dax: fix device-dax region base
  fs/seq_file: fix out-of-bounds read
  mm: memcontrol: avoid unused function warning
  mm: clarify COMPACTION Kconfig text
  treewide: replace config_enabled() with IS_ENABLED() (2nd round)
  printk: fix parsing of "brl=" option
  soft_dirty: fix soft_dirty during THP split
  sysctl: handle error writing UINT_MAX to u32 fields
  get_maintainer: quiet noisy implicit -f vcs_file_exists checking
  byteswap: don't use __builtin_bswap*() with sparse
2016-08-26 23:12:12 -07:00
Linus Torvalds
fd1ae51452 Merge branch 'for-linus' of git://git.kernel.dk/linux-block
Pull block fixes from Jens Axboe:
 "Here's a set of block fixes for the current 4.8-rc release.  This
  contains:

   - a fix for a secure erase regression, from Adrian.

   - a fix for an mmc use-after-free bug regression, also from Adrian.

   - potential zero pointer deference in bdev freezing, from Andrey.

   - a race fix for blk_set_queue_dying() from Bart.

   - a set of xen blkfront fixes from Bob Liu.

   - three small fixes for bcache, from Eric and Kent.

   - a fix for a potential invalid NVMe state transition, from Gabriel.

   - blk-mq CPU offline fix, preventing us from issuing and completing a
     request on the wrong queue.  From me.

   - revert two previous floppy changes, since they caused a user
     visibile regression.  A better fix is in the works.

   - ensure that we don't send down bios that have more than 256
     elements in them.  Fixes a crash with bcache, for example.  From
     Ming.

   - a fix for deferencing an error pointer with cgroup writeback.
     Fixes a regression.  From Vegard"

* 'for-linus' of git://git.kernel.dk/linux-block:
  mmc: fix use-after-free of struct request
  Revert "floppy: refactor open() flags handling"
  Revert "floppy: fix open(O_ACCMODE) for ioctl-only open"
  fs/block_dev: fix potential NULL ptr deref in freeze_bdev()
  blk-mq: improve warning for running a queue on the wrong CPU
  blk-mq: don't overwrite rq->mq_ctx
  block: make sure a big bio is split into at most 256 bvecs
  nvme: Fix nvme_get/set_features() with a NULL result pointer
  bdev: fix NULL pointer dereference
  xen-blkfront: free resources if xlvbd_alloc_gendisk fails
  xen-blkfront: introduce blkif_set_queue_limits()
  xen-blkfront: fix places not updated after introducing 64KB page granularity
  bcache: pr_err: more meaningful error message when nr_stripes is invalid
  bcache: RESERVE_PRIO is too small by one when prio_buckets() is a power of two.
  bcache: register_bcache(): call blkdev_put() when cache_alloc() fails
  block: Fix race triggered by blk_set_queue_dying()
  block: Fix secure erase
  nvme: Prevent controller state invalid transition
2016-08-26 18:50:07 -07:00
Nicolas Iooss
ae6c33ba6e printk: fix parsing of "brl=" option
Commit bbeddf52ad ("printk: move braille console support into separate
braille.[ch] files") moved the parsing of braille-related options into
_braille_console_setup(), changing the type of variable str from char*
to char**.  In this commit, memcmp(str, "brl,", 4) was correctly updated
to memcmp(*str, "brl,", 4) but not memcmp(str, "brl=", 4).

Update the code to make "brl=" option work again and replace memcmp()
with strncmp() to make the compiler able to detect such an issue.

Fixes: bbeddf52ad ("printk: move braille console support into separate braille.[ch] files")
Link: http://lkml.kernel.org/r/20160823165700.28952-1-nicolas.iooss_linux@m4x.org
Signed-off-by: Nicolas Iooss <nicolas.iooss_linux@m4x.org>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-08-26 17:39:35 -07:00
Subash Abhinov Kasiviswanathan
e7d316a02f sysctl: handle error writing UINT_MAX to u32 fields
We have scripts which write to certain fields on 3.18 kernels but this
seems to be failing on 4.4 kernels.  An entry which we write to here is
xfrm_aevent_rseqth which is u32.

  echo 4294967295  > /proc/sys/net/core/xfrm_aevent_rseqth

Commit 230633d109 ("kernel/sysctl.c: detect overflows when converting
to int") prevented writing to sysctl entries when integer overflow
occurs.  However, this does not apply to unsigned integers.

Heinrich suggested that we introduce a new option to handle 64 bit
limits and set min as 0 and max as UINT_MAX.  This might not work as it
leads to issues similar to __do_proc_doulongvec_minmax.  Alternatively,
we would need to change the datatype of the entry to 64 bit.

  static int __do_proc_doulongvec_minmax(void *data, struct ctl_table
  {
      i = (unsigned long *) data;   //This cast is causing to read beyond the size of data (u32)
      vleft = table->maxlen / sizeof(unsigned long); //vleft is 0 because maxlen is sizeof(u32) which is lesser than sizeof(unsigned long) on x86_64.

Introduce a new proc handler proc_douintvec.  Individual proc entries
will need to be updated to use the new handler.

[akpm@linux-foundation.org: coding-style fixes]
Fixes: 230633d109 ("kernel/sysctl.c:detect overflows when converting to int")
Link: http://lkml.kernel.org/r/1471479806-5252-1-git-send-email-subashab@codeaurora.org
Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>
Cc: Heinrich Schuchardt <xypron.glpk@gmx.de>
Cc: Kees Cook <keescook@chromium.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Ingo Molnar <mingo@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-08-26 17:39:35 -07:00
Josh Poimboeuf
2992ef29ae livepatch/module: make TAINT_LIVEPATCH module-specific
There's no reliable way to determine which module tainted the kernel
with TAINT_LIVEPATCH.  For example, /sys/module/<klp module>/taint
doesn't report it.  Neither does the "mod -t" command in the crash tool.

Make it crystal clear who the guilty party is by associating
TAINT_LIVEPATCH with any module which sets the "livepatch" modinfo
attribute.  The flag will still get set in the kernel like before, but
now it also sets the same flag in mod->taint.

Note that now the taint flag gets set when the module is loaded rather
than when it's enabled.

I also renamed find_livepatch_modinfo() to check_modinfo_livepatch() to
better reflect its purpose: it's basically a livepatch-specific
sub-function of check_modinfo().

Reported-by: Chunyu Hu <chuhu@redhat.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Acked-by: Jessica Yu <jeyu@redhat.com>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2016-08-26 14:42:08 +02:00
James Morse
d391e55229 cpu/hotplug: Allow suspend/resume CPU to be specified
disable_nonboot_cpus() assumes that the lowest numbered online CPU is
the boot CPU, and that this is the correct CPU to run any power
management code on.

On x86 this is always correct, as CPU0 cannot (easily) by taken offline.

On arm64 CPU0 can be taken offline. For hibernate/resume this means we
may hibernate on a CPU other than CPU0. If the system is rebooted with
kexec 'CPU0' will be assigned to a different physical CPU. This
complicates hibernate/resume as now we can't trust the CPU numbers.
Arch code can find the correct physical CPU, and ensure it is online
before resume from hibernate begins, but also needs to influence
disable_nonboot_cpus()s choice of CPU.

Rename disable_nonboot_cpus() as freeze_secondary_cpus() and add an
argument indicating which CPU should be left standing. Follow the logic
in migrate_to_reboot_cpu() to use the lowest numbered online CPU if the
requested CPU is not online.
Add disable_nonboot_cpus() as an inline function that has the existing
behaviour.

Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
2016-08-26 11:20:11 +01:00
Will Deacon
8b6a3fe8fa perf/core: Use this_cpu_ptr() when stopping AUX events
When tearing down an AUX buf for an event via perf_mmap_close(),
__perf_event_output_stop() is called on the event's CPU to ensure that
trace generation is halted before the process of unmapping and
freeing the buffer pages begins.

The callback is performed via cpu_function_call(), which ensures that it
runs with interrupts disabled and is therefore not preemptible.
Unfortunately, the current code grabs the per-cpu context pointer using
get_cpu_ptr(), which unnecessarily disables preemption and doesn't pair
the call with put_cpu_ptr(), leading to a preempt_count() imbalance and
a BUG when freeing the AUX buffer later on:

  WARNING: CPU: 1 PID: 2249 at kernel/events/ring_buffer.c:539 __rb_free_aux+0x10c/0x120
  Modules linked in:
  [...]
  Call Trace:
   [<ffffffff813379dd>] dump_stack+0x4f/0x72
   [<ffffffff81059ff6>] __warn+0xc6/0xe0
   [<ffffffff8105a0c8>] warn_slowpath_null+0x18/0x20
   [<ffffffff8112761c>] __rb_free_aux+0x10c/0x120
   [<ffffffff81128163>] rb_free_aux+0x13/0x20
   [<ffffffff8112515e>] perf_mmap_close+0x29e/0x2f0
   [<ffffffff8111da30>] ? perf_iterate_ctx+0xe0/0xe0
   [<ffffffff8115f685>] remove_vma+0x25/0x60
   [<ffffffff81161796>] exit_mmap+0x106/0x140
   [<ffffffff8105725c>] mmput+0x1c/0xd0
   [<ffffffff8105cac3>] do_exit+0x253/0xbf0
   [<ffffffff8105e32e>] do_group_exit+0x3e/0xb0
   [<ffffffff81068d49>] get_signal+0x249/0x640
   [<ffffffff8101c273>] do_signal+0x23/0x640
   [<ffffffff81905f42>] ? _raw_write_unlock_irq+0x12/0x30
   [<ffffffff81905f69>] ? _raw_spin_unlock_irq+0x9/0x10
   [<ffffffff81901896>] ? __schedule+0x2c6/0x710
   [<ffffffff810022a4>] exit_to_usermode_loop+0x74/0x90
   [<ffffffff81002a56>] prepare_exit_to_usermode+0x26/0x30
   [<ffffffff81906d1b>] retint_user+0x8/0x10

This patch uses this_cpu_ptr() instead of get_cpu_ptr(), since preemption is
already disabled by the caller.

Signed-off-by: Will Deacon <will.deacon@arm.com>
Reviewed-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Fixes: 95ff4ca26c ("perf/core: Free AUX pages in unmap path")
Link: http://lkml.kernel.org/r/20160824091905.GA16944@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-24 15:03:10 +02:00
Brian Gerst
01175255fd sched: Remove __schedule() non-standard frame annotation
Now that the x86 switch_to() uses the standard C calling convention,
the STACK_FRAME_NON_STANDARD() annotation is no longer needed.

Suggested-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Brian Gerst <brgerst@gmail.com>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1471106302-10159-8-git-send-email-brgerst@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-24 12:31:51 +02:00
Vegard Nossum
b2d4c2edb2 locking/hung_task: Show all locks
When we get a hung task it can often be valuable to see _all_ the held
locks on the system (in case we are being blocked on trying to acquire
one), e.g. with this patch we can immediately see where the problem is
below:

    INFO: task trinity-c3:14933 blocked for more than 120 seconds.
	  Not tainted 4.8.0-rc1+ #135
    "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
    trinity-c3      D ffff88010c16fc88     0 14933      1 0x00080004
     ffff88010c16fc88 000000003b9aca00 0000000000000000 0000000000000296
     00000000776cdf88 ffff88011a520ae0 ffff88011a520b08 ffff88011a520198
     ffffffff867d7f00 ffff88011942c080 ffff880116841580 ffff88010c168000
    Call Trace:
     [<ffffffff845e9d37>] schedule+0x77/0x230
     [<ffffffff833cb8b9>] __lock_sock+0x129/0x250
     [<ffffffff833cb790>] ? __sk_destruct+0x450/0x450
     [<ffffffff81408ac0>] ? wake_bit_function+0x2e0/0x2e0
     [<ffffffff833d832b>] lock_sock_nested+0xeb/0x120
     [<ffffffff83bad815>] irda_setsockopt+0x65/0xb40
     [<ffffffff833c6c09>] SyS_setsockopt+0x139/0x230
     [<ffffffff833c6ad0>] ? SyS_recv+0x20/0x20
     [<ffffffff81004660>] ? trace_event_raw_event_sys_enter+0xb90/0xb90
     [<ffffffff823c7023>] ? __this_cpu_preempt_check+0x13/0x20
     [<ffffffff8162ee60>] ? __context_tracking_exit.part.3+0x30/0x1b0
     [<ffffffff833c6ad0>] ? SyS_recv+0x20/0x20
     [<ffffffff81007bd3>] do_syscall_64+0x1b3/0x4b0
     [<ffffffff845f84aa>] entry_SYSCALL64_slow_path+0x25/0x25

    Showing all locks held in the system:
    2 locks held by khungtaskd/563:
     #0:  (rcu_read_lock){......}, at: [<ffffffff81534ce6>] watchdog+0x106/0x910
     #1:  (tasklist_lock){......}, at: [<ffffffff8141b3c4>] debug_show_all_locks+0x74/0x360
    1 lock held by trinity-c0/19280:
     #0:  (sk_lock-AF_IRDA){......}, at: [<ffffffff83bab7c6>] irda_accept+0x176/0x10f0
    1 lock held by trinity-c0/12865:
     #0:  (sk_lock-AF_IRDA){......}, at: [<ffffffff83bab7c6>] irda_accept+0x176/0x10f0

Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mandeep Singh Baines <msb@chromium.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1471538460-7505-1-git-send-email-vegard.nossum@oracle.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-24 12:16:13 +02:00
Josh Poimboeuf
223918e32a ftrace: Add ftrace_graph_ret_addr() stack unwinding helpers
When function graph tracing is enabled for a function, ftrace modifies
the stack by replacing the original return address with the address of a
hook function (return_to_handler).

Stack unwinders need a way to get the original return address.  Add an
arch-independent helper function for that named ftrace_graph_ret_addr().

This adds two variations of the function: one depends on
HAVE_FUNCTION_GRAPH_RET_ADDR_PTR, and the other relies on an index state
variable.

The former is recommended because, in some cases, the latter can cause
problems when the unwinder skips stack frames.  It can get out of sync
with the ret_stack index and wrong addresses can be reported for the
stack trace.

Once all arches have been ported to use
HAVE_FUNCTION_GRAPH_RET_ADDR_PTR, we can get rid of the distinction.

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Byungchul Park <byungchul.park@lge.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nilay Vaish <nilayvaish@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/36bd90f762fc5e5af3929e3797a68a64906421cf.1471607358.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-24 12:15:14 +02:00
Josh Poimboeuf
9a7c348ba6 ftrace: Add return address pointer to ftrace_ret_stack
Storing this value will help prevent unwinders from getting out of sync
with the function graph tracer ret_stack.  Now instead of needing a
stateful iterator, they can compare the return address pointer to find
the right ret_stack entry.

Note that an array of 50 ftrace_ret_stack structs is allocated for every
task.  So when an arch implements this, it will add either 200 or 400
bytes of memory usage per task (depending on whether it's a 32-bit or
64-bit platform).

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Byungchul Park <byungchul.park@lge.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nilay Vaish <nilayvaish@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/a95cfcc39e8f26b89a430c56926af0bb217bc0a1.1471607358.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-24 12:15:14 +02:00
Josh Poimboeuf
daa460a88c ftrace: Only allocate the ret_stack 'fp' field when needed
This saves some memory when HAVE_FUNCTION_GRAPH_FP_TEST isn't defined.
On x86_64 with newer versions of gcc which have -mfentry, it saves 400
bytes per task.

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Byungchul Park <byungchul.park@lge.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nilay Vaish <nilayvaish@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/5c7747d9ea7b5cb47ef0a8ce8a6cea6bf7aa94bf.1471607358.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-24 12:15:14 +02:00
Josh Poimboeuf
e4a744ef2f ftrace: Remove CONFIG_HAVE_FUNCTION_GRAPH_FP_TEST from config
Make HAVE_FUNCTION_GRAPH_FP_TEST a normal define, independent from
kconfig.  This removes some config file pollution and simplifies the
checking for the fp test.

Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Byungchul Park <byungchul.park@lge.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nilay Vaish <nilayvaish@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/2c4e5f05054d6d367f702fd153af7a0109dd5c81.1471607358.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-24 12:15:13 +02:00
Andy Lutomirski
ba14a194a4 fork: Add generic vmalloced stack support
If CONFIG_VMAP_STACK=y is selected, kernel stacks are allocated with
__vmalloc_node_range().

Grsecurity has had a similar feature (called GRKERNSEC_KSTACKOVERFLOW=y)
for a long time.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/14c07d4fd173a5b117f51e8b939f9f4323e39899.1470907718.git.luto@kernel.org
[ Minor edits. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-24 12:11:41 +02:00
John Stultz
a4f8f6667f timekeeping: Cap array access in timekeeping_debug
It was reported that hibernation could fail on the 2nd attempt, where the
system hangs at hibernate() -> syscore_resume() -> i8237A_resume() ->
claim_dma_lock(), because the lock has already been taken.

However there is actually no other process would like to grab this lock on
that problematic platform.

Further investigation showed that the problem is triggered by setting
/sys/power/pm_trace to 1 before the 1st hibernation.

Since once pm_trace is enabled, the rtc becomes unmeaningful after suspend,
and meanwhile some BIOSes would like to adjust the 'invalid' RTC (e.g, smaller
than 1970) to the release date of that motherboard during POST stage, thus
after resumed, it may seem that the system had a significant long sleep time
which is a completely meaningless value.

Then in timekeeping_resume -> tk_debug_account_sleep_time, if the bit31 of the
sleep time happened to be set to 1, fls() returns 32 and we add 1 to
sleep_time_bin[32], which causes an out of bounds array access and therefor
memory being overwritten.

As depicted by System.map:
0xffffffff81c9d080 b sleep_time_bin
0xffffffff81c9d100 B dma_spin_lock
the dma_spin_lock.val is set to 1, which caused this problem.

This patch adds a sanity check in tk_debug_account_sleep_time()
to ensure we don't index past the sleep_time_bin array.

[jstultz: Problem diagnosed and original patch by Chen Yu, I've solved the
 issue slightly differently, but borrowed his excelent explanation of the
 issue here.]

Fixes: 5c83545f24 "power: Add option to log time spent in suspend"
Reported-by: Janek Kozicki <cosurgi@gmail.com>
Reported-by: Chen Yu <yu.c.chen@intel.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Cc: linux-pm@vger.kernel.org
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Xunlei Pang <xpang@redhat.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: stable <stable@vger.kernel.org>
Cc: Zhang Rui <rui.zhang@intel.com>
Link: http://lkml.kernel.org/r/1471993702-29148-3-git-send-email-john.stultz@linaro.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-08-24 09:34:32 +02:00
John Stultz
27727df240 timekeeping: Avoid taking lock in NMI path with CONFIG_DEBUG_TIMEKEEPING
When I added some extra sanity checking in timekeeping_get_ns() under
CONFIG_DEBUG_TIMEKEEPING, I missed that the NMI safe __ktime_get_fast_ns()
method was using timekeeping_get_ns().

Thus the locking added to the debug checks broke the NMI-safety of
__ktime_get_fast_ns().

This patch open-codes the timekeeping_get_ns() logic for
__ktime_get_fast_ns(), so can avoid any deadlocks in NMI.

Fixes: 4ca22c2648 "timekeeping: Add warnings when overflows or underflows are observed"
Reported-by: Steven Rostedt <rostedt@goodmis.org>
Reported-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Cc: stable <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/1471993702-29148-2-git-send-email-john.stultz@linaro.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-08-24 09:34:31 +02:00
Masami Hiramatsu
bdca79c2bf ftrace: kprobe: uprobe: Show u8/u16/u32/u64 types in decimal
Change kprobe/uprobe-tracer to show the arguments type-casted
with u8/u16/u32/u64 in decimal digits instead of hexadecimal.

To minimize compatibility issue, the arguments without type
casting are typed by x64 (or x32 for 32bit arch) by default.

Note: all arguments set by old perf probe without types are
shown in decimal by default.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Hemant Kumar <hemant@linux.vnet.ibm.com>
Cc: Naohiro Aota <naohiro.aota@hgst.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/147151076135.12957.14684546093034343894.stgit@devbox
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2016-08-23 17:06:38 -03:00
Masami Hiramatsu
8642562555 ftrace: probe: Add README entries for k/uprobe-events
Add README entries for kprobe-events and uprobe-events.
This allows user to check what options can be acceptable
for running kernel.
E.g. perf tools can choose correct types for the kernel.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Hemant Kumar <hemant@linux.vnet.ibm.com>
Cc: Naohiro Aota <naohiro.aota@hgst.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/147151069524.12957.12957179170304055028.stgit@devbox
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2016-08-23 15:39:57 -03:00
Masami Hiramatsu
17ce3dc7e5 ftrace: kprobe: uprobe: Add x8/x16/x32/x64 for hexadecimal types
Add x8/x16/x32/x64 for hexadecimal type casting to kprobe/uprobe event
tracer.

These type casts can be used for integer arguments for explicitly
showing them in hexadecimal digits in formatted text.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Hemant Kumar <hemant@linux.vnet.ibm.com>
Cc: Naohiro Aota <naohiro.aota@hgst.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/147151067029.12957.11591314629326414783.stgit@devbox
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2016-08-23 15:38:09 -03:00
SeongJae Park
a56fefa260 rcuperf: Consistently insert space between flag and message
A few rcuperf dmesg output messages have no space between the flag and
the start of the message. In contrast, every other messages consistently
supplies a single space.  This difference makes rcuperf dmesg output
hard to read and to mechanically parse.  This commit therefore fixes
this problem by modifying a pr_alert() call and PERFOUT_STRING() macro
function to provide that single space.

Signed-off-by: SeongJae Park <sj38.park@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2016-08-22 10:06:16 -07:00
SeongJae Park
472213a675 rcutorture: Print out barrier error as document says
Tests for rcu_barrier() were introduced by commit fae4b54f28 ("rcu:
Introduce rcutorture testing for rcu_barrier()").  This commit updated
the documentation to say that the "rtbe" field in rcutorture's dmesg
output indicates test failure.  However, the code was not updated, only
the documentation.  This commit therefore updates the code to match the
updated documentation.

Signed-off-by: SeongJae Park <sj38.park@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2016-08-22 10:03:37 -07:00
Paul E. McKenney
4ffa669924 torture: Add task state to writer-task stall printk()s
This commit adds a dump of the scheduler state for stalled rcutorture
writer tasks.  This addition provides yet more debug for the intermittent
"failures to proceed", where grace periods move ahead but the rcutorture
writer tasks fail to do so.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2016-08-22 10:02:59 -07:00
Paul E. McKenney
31257c3c8b torture: Convert torture_shutdown() to hrtimer
Upcoming changes to the timer wheel introduce significant inaccuracy
and possibly also an ultimate limit on timeout duration.  This is a
problem for the current implementation of torture_shutdown() because
(1) shutdown times are user-specified, and can therefore be quite long,
and (2) the torture scripting will kill a test instance that runs for
more than a few minutes longer than scheduled.  This commit therefore
converts the torture_shutdown() timed waits to an hrtimer, thus avoiding
too-short torture test runs as well as death by scripting.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
2016-08-22 10:01:49 -07:00
Sebastian Andrzej Siewior
0ffd374b22 rcutorture: Convert to hotplug state machine
Install the callbacks via the state machine and let the core invoke
the callbacks on the already online CPUs.

Cc: Josh Triplett <josh@joshtriplett.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2016-08-22 09:52:12 -07:00
Sebastian Andrzej Siewior
0c6d4576c4 cpu/hotplug: Get rid of CPU_STARTING reference
CPU_STARTING is scheduled for removal. There is no use of it in drivers
and core code uses it only for compatibility with old-style CPU-hotplug
notifiers.  This patch removes therefore removes CPU_STARTING from an
RCU-related comment.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2016-08-22 09:50:45 -07:00
Paul E. McKenney
7ec99de36f rcu: Provide exact CPU-online tracking for RCU
Up to now, RCU has assumed that the CPU-online process makes it from
CPU_UP_PREPARE to set_cpu_online() within one jiffy.  Given the recent
rise of virtualized environments, this assumption is very clearly
obsolete.  Failing to meet this deadline can result in RCU paying
attention to an incoming CPU for one jiffy, then ignoring it until the
grace period following the one in which that CPU sets itself online.
This situation might prove to be fatally disappointing to any RCU
read-side critical sections that had the misfortune to execute during
the time in which RCU was ignoring the slow-to-come-online CPU.

This commit therefore updates RCU's internal CPU state-tracking
information at notify_cpu_starting() time, thus providing RCU with
an exact transition of the CPU's state from offline to online.

Note that this means that incoming CPUs must not use RCU read-side
critical section (other than those of SRCU) until notify_cpu_starting()
time.  Note also that the CPU_STARTING notifiers -are- allowed to use
RCU read-side critical sections.  (Of course, CPU-hotplug notifiers are
rapidly becoming obsolete, so you need to act fast!)

If a given architecture or CPU family needs to use RCU read-side
critical sections earlier, the call to rcu_cpu_starting() from
notify_cpu_starting() will need to be architecture-specific, with
architectures that need early use being required to hand-place
the call to rcu_cpu_starting() at some point preceding the call to
notify_cpu_starting().

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2016-08-22 09:36:57 -07:00
Paul E. McKenney
3563a438f1 rcu: Avoid redundant quiescent-state chasing
Currently, __note_gp_changes() checks to see if the CPU has slept through
multiple grace periods.  If it has, it resynchronizes that CPU's view
of the grace-period state, which includes whether or not the current
grace period needs a quiescent state from this CPU.  The fact of this
need (or lack thereof) needs to be in two places, rdp->cpu_no_qs.b.norm
and rdp->core_needs_qs.  The former tells RCU's context-switch code to
go get a quiescent state and the latter says that it needs to be reported.
The current code unconditionally sets the former to true, but correctly
sets the latter.

This does not result in failures, but it does unnecessarily increase
the amount of work done on average at context-switch time.  This commit
therefore correctly sets both fields.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2016-08-22 09:35:57 -07:00
Paul Gortmaker
e77b704125 rcu: Don't use modular infrastructure in non-modular code
The Kconfig currently controlling compilation of tree.c is:

init/Kconfig:config TREE_RCU
init/Kconfig:   bool

...and update.c and sync.c are "obj-y" meaning that none are ever
built as a module by anyone.

Since MODULE_ALIAS is a no-op for non-modular code, we can remove
them from these files.

We leave moduleparam.h behind since the files instantiate some boot
time configuration parameters with module_param() still.

Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2016-08-22 09:35:27 -07:00
Paul E. McKenney
379d9ecb3c sched: Make wake_up_nohz_cpu() handle CPUs going offline
Both timers and hrtimers are maintained on the outgoing CPU until
CPU_DEAD time, at which point they are migrated to a surviving CPU.  If a
mod_timer() executes between CPU_DYING and CPU_DEAD time, x86 systems
will splat in native_smp_send_reschedule() when attempting to wake up
the just-now-offlined CPU, as shown below from a NO_HZ_FULL kernel:

[ 7976.741556] WARNING: CPU: 0 PID: 661 at /home/paulmck/public_git/linux-rcu/arch/x86/kernel/smp.c:125 native_smp_send_reschedule+0x39/0x40
[ 7976.741595] Modules linked in:
[ 7976.741595] CPU: 0 PID: 661 Comm: rcu_torture_rea Not tainted 4.7.0-rc2+ #1
[ 7976.741595] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
[ 7976.741595]  0000000000000000 ffff88000002fcc8 ffffffff8138ab2e 0000000000000000
[ 7976.741595]  0000000000000000 ffff88000002fd08 ffffffff8105cabc 0000007d1fd0ee18
[ 7976.741595]  0000000000000001 ffff88001fd16d40 ffff88001fd0ee00 ffff88001fd0ee00
[ 7976.741595] Call Trace:
[ 7976.741595]  [<ffffffff8138ab2e>] dump_stack+0x67/0x99
[ 7976.741595]  [<ffffffff8105cabc>] __warn+0xcc/0xf0
[ 7976.741595]  [<ffffffff8105cb98>] warn_slowpath_null+0x18/0x20
[ 7976.741595]  [<ffffffff8103cba9>] native_smp_send_reschedule+0x39/0x40
[ 7976.741595]  [<ffffffff81089bc2>] wake_up_nohz_cpu+0x82/0x190
[ 7976.741595]  [<ffffffff810d275a>] internal_add_timer+0x7a/0x80
[ 7976.741595]  [<ffffffff810d3ee7>] mod_timer+0x187/0x2b0
[ 7976.741595]  [<ffffffff810c89dd>] rcu_torture_reader+0x33d/0x380
[ 7976.741595]  [<ffffffff810c66f0>] ? sched_torture_read_unlock+0x30/0x30
[ 7976.741595]  [<ffffffff810c86a0>] ? rcu_bh_torture_read_lock+0x80/0x80
[ 7976.741595]  [<ffffffff8108068f>] kthread+0xdf/0x100
[ 7976.741595]  [<ffffffff819dd83f>] ret_from_fork+0x1f/0x40
[ 7976.741595]  [<ffffffff810805b0>] ? kthread_create_on_node+0x200/0x200

However, in this case, the wakeup is redundant, because the timer
migration will reprogram timer hardware as needed.  Note that the fact
that preemption is disabled does not avoid the splat, as the offline
operation has already passed both the synchronize_sched() and the
stop_machine() that would be blocked by disabled preemption.

This commit therefore modifies wake_up_nohz_cpu() to avoid attempting
to wake up offline CPUs.  It also adds a comment stating that the
caller must tolerate lost wakeups when the target CPU is going offline,
and suggesting the CPU_DEAD notifier as a recovery mechanism.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
2016-08-22 09:35:26 -07:00
Jisheng Zhang
94d4477673 rcu: Use rcu_gp_kthread_wake() to wake up grace period kthreads
Commit abedf8e241 ("rcu: Use simple wait queues where possible in
rcutree") converts Tree RCU's wait queues to simple wait queues,
but it incorrectly reverts the commit 2aa792e6fa ("rcu: Use
rcu_gp_kthread_wake() to wake up grace period kthreads").  This can
result in redundant self-wakeups.

This commit therefore replaces the simple wait-queue wakeups with
rcu_gp_kthread_wake(), thus avoiding the redundant wakeups.

Signed-off-by: Jisheng Zhang <jszhang@marvell.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2016-08-22 09:33:46 -07:00
Paul E. McKenney
385c859f67 rcu: Use RCU's online-CPU state for expedited IPI retry
This commit improves the accuracy of the interaction between CPU hotplug
operations and RCU's expedited grace periods by using RCU's online-CPU
state to determine when failed IPIs should be retried.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2016-08-22 09:30:42 -07:00
Paul E. McKenney
98834b8378 rcu: Exclude RCU-offline CPUs from expedited grace periods
The expedited RCU grace periods currently rely on a failure indication
from smp_call_function_single() to determine that a given CPU is offline.
This works after a fashion, but is more contorted and less precise than
relying on RCU's internal state.  This commit therefore takes a first
step towards relying on internal state.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2016-08-22 09:30:42 -07:00
Paul E. McKenney
24a6cff286 rcu: Make expedited RCU CPU stall warnings respond to controls
The expedited RCU CPU stall warnings currently responds to neither the
panic_on_rcu_stall sysctl setting nor the rcupdate.rcu_cpu_stall_suppress
kernel boot parameter.  This commit therefore updates the expedited code
to respond to these two controls.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2016-08-22 09:30:26 -07:00
Paul E. McKenney
908d2c1fd1 rcu: Stop disabling expedited RCU CPU stall warnings
Now that RCU expedited grace periods are always driven by a workqueue,
there is no need to account for signal reception, and thus no need
to disable expedited RCU CPU stall warnings due to signal reception.
This commit therefore removes the signal-reception checks, leaving a
WARN_ON() to catch possible future bugs.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2016-08-22 09:30:26 -07:00
Paul E. McKenney
8b355e3bc1 rcu: Drive expedited grace periods from workqueue
The current implementation of expedited grace periods has the user
task drive the grace period.  This works, but has downsides: (1) The
user task must awaken tasks piggybacking on this grace period, which
can result in latencies rivaling that of the grace period itself, and
(2) User tasks can receive signals, which interfere with RCU CPU stall
warnings.

This commit therefore uses workqueues to drive the grace periods, so
that the user task need not do the awakening.  A subsequent commit
will remove the now-unnecessary code allowing for signals.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2016-08-22 09:30:25 -07:00
Paul E. McKenney
f7b8eb847e rcu: Consolidate expedited grace period machinery
The functions synchronize_rcu_expedited() and synchronize_sched_expedited()
have nearly identical code.  This commit therefore consolidates this code
into a new _synchronize_rcu_expedited() function.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2016-08-22 09:30:11 -07:00
Ding Tianhong
bedc196915 rcu: Fix soft lockup for rcu_nocb_kthread
Carrying out the following steps results in a softlockup in the
RCU callback-offload (rcuo) kthreads:

1. Connect to ixgbevf, and set the speed to 10Gb/s.
2. Use ifconfig to bring the nic up and down repeatedly.

[  317.005148] IPv6: ADDRCONF(NETDEV_CHANGE): eth2: link becomes ready
[  368.106005] BUG: soft lockup - CPU#1 stuck for 22s! [rcuos/1:15]
[  368.106005] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[  368.106005] task: ffff88057dd8a220 ti: ffff88057dd9c000 task.ti: ffff88057dd9c000
[  368.106005] RIP: 0010:[<ffffffff81579e04>]  [<ffffffff81579e04>] fib_table_lookup+0x14/0x390
[  368.106005] RSP: 0018:ffff88061fc83ce8  EFLAGS: 00000286
[  368.106005] RAX: 0000000000000001 RBX: 00000000020155c0 RCX: 0000000000000001
[  368.106005] RDX: ffff88061fc83d50 RSI: ffff88061fc83d70 RDI: ffff880036d11a00
[  368.106005] RBP: ffff88061fc83d08 R08: 0000000000000001 R09: 0000000000000000
[  368.106005] R10: ffff880036d11a00 R11: ffffffff819e0900 R12: ffff88061fc83c58
[  368.106005] R13: ffffffff816154dd R14: ffff88061fc83d08 R15: 00000000020155c0
[  368.106005] FS:  0000000000000000(0000) GS:ffff88061fc80000(0000) knlGS:0000000000000000
[  368.106005] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  368.106005] CR2: 00007f8c2aee9c40 CR3: 000000057b222000 CR4: 00000000000407e0
[  368.106005] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  368.106005] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
[  368.106005] Stack:
[  368.106005]  00000000010000c0 ffff88057b766000 ffff8802e380b000 ffff88057af03e00
[  368.106005]  ffff88061fc83dc0 ffffffff815349a6 ffff88061fc83d40 ffffffff814ee146
[  368.106005]  ffff8802e380af00 00000000e380af00 ffffffff819e0900 020155c0010000c0
[  368.106005] Call Trace:
[  368.106005]  <IRQ>
[  368.106005]
[  368.106005]  [<ffffffff815349a6>] ip_route_input_noref+0x516/0xbd0
[  368.106005]  [<ffffffff814ee146>] ? skb_release_data+0xd6/0x110
[  368.106005]  [<ffffffff814ee20a>] ? kfree_skb+0x3a/0xa0
[  368.106005]  [<ffffffff8153698f>] ip_rcv_finish+0x29f/0x350
[  368.106005]  [<ffffffff81537034>] ip_rcv+0x234/0x380
[  368.106005]  [<ffffffff814fd656>] __netif_receive_skb_core+0x676/0x870
[  368.106005]  [<ffffffff814fd868>] __netif_receive_skb+0x18/0x60
[  368.106005]  [<ffffffff814fe4de>] process_backlog+0xae/0x180
[  368.106005]  [<ffffffff814fdcb2>] net_rx_action+0x152/0x240
[  368.106005]  [<ffffffff81077b3f>] __do_softirq+0xef/0x280
[  368.106005]  [<ffffffff8161619c>] call_softirq+0x1c/0x30
[  368.106005]  <EOI>
[  368.106005]
[  368.106005]  [<ffffffff81015d95>] do_softirq+0x65/0xa0
[  368.106005]  [<ffffffff81077174>] local_bh_enable+0x94/0xa0
[  368.106005]  [<ffffffff81114922>] rcu_nocb_kthread+0x232/0x370
[  368.106005]  [<ffffffff81098250>] ? wake_up_bit+0x30/0x30
[  368.106005]  [<ffffffff811146f0>] ? rcu_start_gp+0x40/0x40
[  368.106005]  [<ffffffff8109728f>] kthread+0xcf/0xe0
[  368.106005]  [<ffffffff810971c0>] ? kthread_create_on_node+0x140/0x140
[  368.106005]  [<ffffffff816147d8>] ret_from_fork+0x58/0x90
[  368.106005]  [<ffffffff810971c0>] ? kthread_create_on_node+0x140/0x140

==================================cut here==============================

It turns out that the rcuos callback-offload kthread is busy processing
a very large quantity of RCU callbacks, and it is not reliquishing the
CPU while doing so.  This commit therefore adds an cond_resched_rcu_qs()
within the loop to allow other tasks to run.

Signed-off-by: Ding Tianhong <dingtianhong@huawei.com>
[ paulmck: Substituted cond_resched_rcu_qs for cond_resched. ]
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2016-08-22 07:53:20 -07:00
Christoph Hellwig
3ee0ce2a54 genirq/affinity: Use get/put_online_cpus around cpumask operations
Without locking out CPU mask operations we might end up with an inconsistent
view of the cpumask in the function.

Fixes: 5e385a6ef3: "genirq: Add a helper to spread an affinity mask for MSI/MSI-X vectors"
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: http://lkml.kernel.org/r/1470924405-25728-1-git-send-email-hch@lst.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-08-22 11:22:44 +02:00
Shawn Lin
4396f46c8c genirq: Fix potential memleak when failing to get irq pm
Obviously we should free action here if irq_chip_pm_get failed.

Fixes: be45beb2df: "genirq: Add runtime power management support for IRQ chips"
Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
Cc: Jon Hunter <jonathanh@nvidia.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Link: http://lkml.kernel.org/r/1471854112-13006-1-git-send-email-shawn.lin@rock-chips.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-08-22 11:22:44 +02:00
Linus Torvalds
ac78bc714b Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler fixes from Ingo Molnar:
 "Two cputime fixes - hopefully the last ones"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/cputime: Resync steal time when guest & host lose sync
  sched/cputime: Fix NO_HZ_FULL getrusage() monotonicity regression
2016-08-18 15:07:21 -07:00
Linus Torvalds
0dcb7b6f8f Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf fixes from Ingo Molnar:
 "Mostly tooling fixes, but also start/stop filter related fixes, a perf
  event read() fix, a fix uncovered by fuzzing, and an uprobes leak fix"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/core: Check return value of the perf_event_read() IPI
  perf/core: Enable mapping of the stop filters
  perf/core: Update filters only on executable mmap
  perf/core: Fix file name handling for start/stop filters
  perf/core: Fix event_function_local()
  uprobes: Fix the memcg accounting
  perf intel-pt: Fix occasional decoding errors when tracing system-wide
  tools: Sync kvm related header files for arm64 and s390
  perf probe: Release resources on error when handling exit paths
  perf probe: Check for dup and fdopen failures
  perf symbols: Fix annotation of objects with debuginfo files
  perf script: Don't disable use_callchain if input is pipe
  perf script: Show proper message when failed list scripts
  perf jitdump: Add the right header to get the major()/minor() definitions
  perf ppc64le: Fix build failure when libelf is not present
  perf tools mem: Fix -t store option for record command
  perf intel-pt: Fix ip compression
2016-08-18 15:04:53 -07:00
Jessica Yu
255e732c61 livepatch: use arch_klp_init_object_loaded() to finish arch-specific tasks
Introduce arch_klp_init_object_loaded() to complete any additional
arch-specific tasks during patching. Architecture code may override this
function.

Signed-off-by: Jessica Yu <jeyu@redhat.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2016-08-18 23:41:55 +02:00
Linus Torvalds
395c434292 Power management updates for v4.8-rc3
- Fix a hibernate core regression resulting from uncovering a
    latent bug in its implementation of memory bitmaps by a recent
    commit (James Morse).
 
  - Use __pa() to compute a physical address in the x86-64 code
    finalizing resume from hibernation (Rafael Wysocki).
 
  - Update power management documentation related to system sleep
    states to remove outdated information from it and to add a
    description of a recently introduced hibernation debug feature
    to it (Rafael Wysocki).
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Merge tag 'pm-4.8-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull power management fixes from Rafael Wysocki:
 "More hibernation-related material: one fix for a recent regression in
  the core, one small cleanup of the x86-64 resume code and a
  documentation update.

  Specifics:

   - Fix a hibernate core regression resulting from uncovering a latent
     bug in its implementation of memory bitmaps by a recent commit
     (James Morse).

   - Use __pa() to compute a physical address in the x86-64 code
     finalizing resume from hibernation (Rafael Wysocki).

   - Update power management documentation related to system sleep
     states to remove outdated information from it and to add a
     description of a recently introduced hibernation debug feature to
     it (Rafael Wysocki)"

* tag 'pm-4.8-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  PM / hibernate: Fix rtree_next_node() to avoid walking off list ends
  x86/power/64: Use __pa() for physical address computation
  PM / sleep: Update some system sleep documentation
2016-08-18 11:09:43 -07:00
Davidlohr Bueso
70800c3c0c locking/rwsem: Scan the wait_list for readers only once
When wanting to wakeup readers, __rwsem_mark_wakeup() currently
iterates the wait_list twice while looking to wakeup the first N
queued reader-tasks. While this can be quite inefficient, it was
there such that a awoken reader would be first and foremost
acknowledged by the lock counter.

Keeping the same logic, we can further benefit from the use of
wake_qs and avoid entirely the first wait_list iteration that sets
the counter as wake_up_process() isn't going to occur right away,
and therefore we maintain the counter->list order of going about
things.

Other than saving cycles with O(n) "scanning", this change also
nicely cleans up a good chunk of __rwsem_mark_wakeup(); both
visually and less tedious to read.

For example, the following improvements where seen on some will
it scale microbenchmarks, on a 48-core Haswell:

                                       v4.7              v4.7-rwsem-v1
  Hmean    signal1-processes-8    5792691.42 (  0.00%)  5771971.04 ( -0.36%)
  Hmean    signal1-processes-12   6081199.96 (  0.00%)  6072174.38 ( -0.15%)
  Hmean    signal1-processes-21   3071137.71 (  0.00%)  3041336.72 ( -0.97%)
  Hmean    signal1-processes-48   3712039.98 (  0.00%)  3708113.59 ( -0.11%)
  Hmean    signal1-processes-79   4464573.45 (  0.00%)  4682798.66 (  4.89%)
  Hmean    signal1-processes-110  4486842.01 (  0.00%)  4633781.71 (  3.27%)
  Hmean    signal1-processes-141  4611816.83 (  0.00%)  4692725.38 (  1.75%)
  Hmean    signal1-processes-172  4638157.05 (  0.00%)  4714387.86 (  1.64%)
  Hmean    signal1-processes-203  4465077.80 (  0.00%)  4690348.07 (  5.05%)
  Hmean    signal1-processes-224  4410433.74 (  0.00%)  4687534.43 (  6.28%)

  Stddev   signal1-processes-8       6360.47 (  0.00%)     8455.31 ( 32.94%)
  Stddev   signal1-processes-12      4004.98 (  0.00%)     9156.13 (128.62%)
  Stddev   signal1-processes-21      3273.14 (  0.00%)     5016.80 ( 53.27%)
  Stddev   signal1-processes-48     28420.25 (  0.00%)    26576.22 ( -6.49%)
  Stddev   signal1-processes-79     22038.34 (  0.00%)    18992.70 (-13.82%)
  Stddev   signal1-processes-110    23226.93 (  0.00%)    17245.79 (-25.75%)
  Stddev   signal1-processes-141     6358.98 (  0.00%)     7636.14 ( 20.08%)
  Stddev   signal1-processes-172     9523.70 (  0.00%)     4824.75 (-49.34%)
  Stddev   signal1-processes-203    13915.33 (  0.00%)     9326.33 (-32.98%)
  Stddev   signal1-processes-224    15573.94 (  0.00%)    10613.82 (-31.85%)

Other runs that saw improvements include context_switch and pipe; and
as expected, this is particularly highlighted on larger thread counts
as it becomes more expensive to walk the list twice.

No change in wakeup ordering or semantics.

Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Waiman.Long@hp.com
Cc: dave@stgolabs.net
Cc: jason.low2@hpe.com
Cc: wanpeng.li@hotmail.com
Link: http://lkml.kernel.org/r/1470384285-32163-4-git-send-email-dave@stgolabs.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-18 15:37:11 +02:00
Davidlohr Bueso
c2867bbaf5 locking/rwsem: Remove a few useless comments
Our rwsem code (xadd, at least) is rather well documented, but
there are a few really annoying comments in there that serve
no purpose and we shouldn't bother with them.

Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Waiman.Long@hp.com
Cc: dave@stgolabs.net
Cc: jason.low2@hpe.com
Cc: wanpeng.li@hotmail.com
Link: http://lkml.kernel.org/r/1470384285-32163-3-git-send-email-dave@stgolabs.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-18 15:37:07 +02:00
Davidlohr Bueso
84b23f9b58 locking/rwsem: Return void in __rwsem_mark_wake()
We currently return a rw_semaphore structure, which is the
same lock we passed to the function's argument in the first
place. While there are several functions that choose this
return value, the callers use it, for example, for things
like ERR_PTR. This is not the case for __rwsem_mark_wake(),
and in addition this function is really about the lock
waiters (which we know there are at this point), so its
somewhat odd to be returning the sem structure.

Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Waiman.Long@hp.com
Cc: dave@stgolabs.net
Cc: jason.low2@hpe.com
Cc: wanpeng.li@hotmail.com
Link: http://lkml.kernel.org/r/1470384285-32163-2-git-send-email-dave@stgolabs.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-18 15:37:03 +02:00
Peter Zijlstra
3942a9bd7b locking, rcu, cgroup: Avoid synchronize_sched() in __cgroup_procs_write()
The current percpu-rwsem read side is entirely free of serializing insns
at the cost of having a synchronize_sched() in the write path.

The latency of the synchronize_sched() is too high for cgroups. The
commit 1ed1328792 talks about the write path being a fairly cold path
but this is not the case for Android which moves task to the foreground
cgroup and back around binder IPC calls from foreground processes to
background processes, so it is significantly hotter than human initiated
operations.

Switch cgroup_threadgroup_rwsem into the slow mode for now to avoid the
problem, hopefully it should not be that slow after another commit:

  80127a3968 ("locking/percpu-rwsem: Optimize readers and reduce global impact").

We could just add rcu_sync_enter() into cgroup_init() but we do not want
another synchronize_sched() at boot time, so this patch adds the new helper
which doesn't block but currently can only be called before the first use.

Reported-by: John Stultz <john.stultz@linaro.org>
Reported-by: Dmitry Shmidt <dimitrysh@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Colin Cross <ccross@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rom Lemarchand <romlem@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Todd Kjos <tkjos@google.com>
Link: http://lkml.kernel.org/r/20160811165413.GA22807@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-18 15:36:59 +02:00
Stanislaw Gruszka
a1eb1411b4 sched/cputime: Improve scalability by not accounting thread group tasks pending runtime
Commit:

  d670ec1317 ("posix-cpu-timers: Cure SMP wobbles")

started accounting thread group tasks pending runtime in thread_group_cputime().

Another commit:

  6e998916df ("sched/cputime: Fix clock_nanosleep()/clock_gettime() inconsistency")

updated scheduler runtime statistics (call update_curr()) when reading task pending
runtime. Those changes cause bad performance of SYS_times() and
SYS_clock_gettimes(CLOCK_PROCESS_CPUTIME_ID) syscalls, especially on
larger systems with many CPUs.

While we would like to have cpuclock monotonicity kept i.e. have
problems fixed by above commits stay fixed, we also would like to have
good performance.

However when we notice that change from commit d670ec1317 is not
longer needed to solve problem addressed by that commit, because of
change from the second commit 6e998916df, we can get room for
optimization. Since we update task while reading it's pending runtime
in task_sched_runtime(), clock_gettime(CLOCK_PROCESS_CPUTIME_ID) will
see updated values and on testcase from d670ec1317 process cpuclock
will not be smaller than thread cpuclock.

I tested the patch on testcases from commits d670ec1317,
6e998916df and some other cpuclock/cputimers testcases and
did not found cpuclock monotonicity problems or other malfunction.

This patch has the drawback that we will not provide thread group cputime
up-to-date to the last moment. For example when arming cputime timer,
we will arm it with possibly a bit outdated values and that timer will
trigger earlier compared to behaviour without the patch. However that
was the behaviour before d670ec1317 commit (kernel v3.1) so it's
unlikely to affect applications.

Patch improves related syscall performance, as measured by Giovanni's
benchmarks described in commit:

  6075620b05 ("sched/cputime: Mitigate performance regression in times()/clock_gettime()")

The benchmark results are:

SYS_clock_gettime():

  threads    4.7-rc7     3.18-rc3              4.7-rc7 + prefetch    4.7-rc7 + patch
                         (pre-6e998916dfe3)
  2          3.48        2.23 ( 35.68%)        3.06 ( 11.83%)        1.08 ( 68.81%)
  5          3.33        2.83 ( 14.84%)        3.25 (  2.40%)        0.71 ( 78.55%)
  8          3.37        2.84 ( 15.80%)        3.26 (  3.30%)        0.56 ( 83.49%)
  12         3.32        3.09 (  6.69%)        3.37 ( -1.60%)        0.42 ( 87.28%)
  21         4.01        3.14 ( 21.70%)        3.90 (  2.74%)        0.35 ( 91.35%)
  30         3.63        3.28 (  9.75%)        3.36 (  7.41%)        0.28 ( 92.23%)
  48         3.71        3.02 ( 18.69%)        3.11 ( 16.27%)        0.39 ( 89.39%)
  79         3.75        2.88 ( 23.23%)        3.16 ( 15.74%)        0.46 ( 87.76%)
  110        3.81        2.95 ( 22.62%)        3.25 ( 14.80%)        0.56 ( 85.41%)
  128        3.88        3.05 ( 21.28%)        3.31 ( 14.76%)        0.62 ( 84.10%)

SYS_times():

  threads    4.7-rc7     3.18-rc3              4.7-rc7 + prefetch    4.7-rc7 + patch
                         (pre-6e998916dfe3)
  2          3.65        2.27 ( 37.94%)        3.25 ( 11.03%)        1.62 ( 55.71%)
  5          3.45        2.78 ( 19.34%)        3.17 (  7.92%)        2.33 ( 32.28%)
  8          3.52        2.79 ( 20.66%)        3.22 (  8.69%)        2.06 ( 41.44%)
  12         3.29        3.02 (  8.33%)        3.36 ( -2.04%)        2.00 ( 39.18%)
  21         4.07        3.10 ( 23.86%)        3.92 (  3.78%)        2.07 ( 49.18%)
  30         3.87        3.33 ( 13.80%)        3.40 ( 12.17%)        1.89 ( 51.12%)
  48         3.79        2.96 ( 21.94%)        3.16 ( 16.61%)        1.69 ( 55.46%)
  79         3.88        2.88 ( 25.82%)        3.28 ( 15.42%)        1.60 ( 58.81%)
  110        3.90        2.98 ( 23.73%)        3.38 ( 13.35%)        1.73 ( 55.61%)
  128        4.00        3.10 ( 22.40%)        3.38 ( 15.45%)        1.66 ( 58.52%)

Reported-and-tested-by: Giovanni Gherdovich <ggherdovich@suse.cz>
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Mike Galbraith <mgalbraith@suse.de>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Wanpeng Li <wanpeng.li@hotmail.com>
Link: http://lkml.kernel.org/r/20160817093043.GA25206@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-18 11:53:46 +02:00
Morten Rasmussen
3273163c67 sched/fair: Let asymmetric CPU configurations balance at wake-up
Currently, SD_WAKE_AFFINE always takes priority over wakeup balancing if
SD_BALANCE_WAKE is set on the sched_domains. For asymmetric
configurations SD_WAKE_AFFINE is only desirable if the waking task's
compute demand (utilization) is suitable for the waking CPU and the
previous CPU, and all CPUs within their respective
SD_SHARE_PKG_RESOURCES domains (sd_llc). If not, let wakeup balancing
take over (find_idlest_{group, cpu}()).

This patch makes affine wake-ups conditional on whether both the waker
CPU and the previous CPU has sufficient capacity for the waking task,
or not, assuming that the CPU capacities within an SD_SHARE_PKG_RESOURCES
domain (sd_llc) are homogeneous.

Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dietmar.eggemann@arm.com
Cc: freedom.tan@mediatek.com
Cc: keita.kobayashi.ym@renesas.com
Cc: mgalbraith@suse.de
Cc: sgurrappadi@nvidia.com
Cc: yuyang.du@intel.com
Link: http://lkml.kernel.org/r/1469453670-2660-10-git-send-email-morten.rasmussen@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-18 11:26:56 +02:00
Dietmar Eggemann
cd92bfd3b8 sched/core: Store maximum per-CPU capacity in root domain
To be able to compare the capacity of the target CPU with the highest
available CPU capacity, store the maximum per-CPU capacity in the root
domain.

The max per-CPU capacity should be 1024 for all systems except SMT,
where the capacity is currently based on smt_gain and the number of
hardware threads and is <1024. If SMT can be brought to work with a
per-thread capacity of 1024, this patch can be dropped and replaced by a
hard-coded max capacity of 1024 (=SCHED_CAPACITY_SCALE).

Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: freedom.tan@mediatek.com
Cc: keita.kobayashi.ym@renesas.com
Cc: mgalbraith@suse.de
Cc: sgurrappadi@nvidia.com
Cc: vincent.guittot@linaro.org
Cc: yuyang.du@intel.com
Link: http://lkml.kernel.org/r/26c69258-9947-f830-a53e-0c54e7750646@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-18 11:26:55 +02:00
Morten Rasmussen
9ee1cda5ee sched/core: Enable SD_BALANCE_WAKE for asymmetric capacity systems
A domain with the SD_ASYM_CPUCAPACITY flag set indicate that
sched_groups at this level and below do not include CPUs of all
capacities available (e.g. group containing little-only or big-only CPUs
in big.LITTLE systems). It is therefore necessary to put in more effort
in finding an appropriate CPU at task wake-up by enabling balancing at
wake-up (SD_BALANCE_WAKE) on all lower (child) levels.

Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dietmar.eggemann@arm.com
Cc: freedom.tan@mediatek.com
Cc: keita.kobayashi.ym@renesas.com
Cc: mgalbraith@suse.de
Cc: sgurrappadi@nvidia.com
Cc: vincent.guittot@linaro.org
Cc: yuyang.du@intel.com
Link: http://lkml.kernel.org/r/1469453670-2660-8-git-send-email-morten.rasmussen@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-18 11:26:55 +02:00
Morten Rasmussen
3676b13e85 sched/core: Pass child domain into sd_init()
If behavioural sched_domain flags depend on topology flags set at higher
domain levels we need a way to update the child domain flags. Moving the
child pointer assignment inside sd_init() should make that possible.

Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dietmar.eggemann@arm.com
Cc: freedom.tan@mediatek.com
Cc: keita.kobayashi.ym@renesas.com
Cc: mgalbraith@suse.de
Cc: sgurrappadi@nvidia.com
Cc: vincent.guittot@linaro.org
Cc: yuyang.du@intel.com
Link: http://lkml.kernel.org/r/1469453670-2660-7-git-send-email-morten.rasmussen@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-18 11:26:54 +02:00
Morten Rasmussen
1f6e6c7cb9 sched/core: Introduce SD_ASYM_CPUCAPACITY sched_domain topology flag
Add a topology flag to the sched_domain hierarchy indicating the lowest
domain level where the full range of CPU capacities is represented by
the domain members for asymmetric capacity topologies (e.g. ARM
big.LITTLE).

The flag is intended to indicate that extra care should be taken when
placing tasks on CPUs and this level spans all the different types of
CPUs found in the system (no need to look further up the domain
hierarchy). This information is currently only available through
iterating through the capacities of all the CPUs at parent levels in the
sched_domain hierarchy.

  SD 2      [  0      1      2      3]  SD_ASYM_CPUCAPACITY

  SD 1      [  0      1] [   2      3]  !SD_ASYM_CPUCAPACITY

  CPU:         0      1      2      3
  capacity:  756    756   1024   1024

If the topology in the example above is duplicated to create an eight
CPU example with third sched_domain level on top (SD 3), this level
should not have the flag set (!SD_ASYM_CPUCAPACITY) as its two group
would both have all CPU capacities represented within them.

Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dietmar.eggemann@arm.com
Cc: freedom.tan@mediatek.com
Cc: keita.kobayashi.ym@renesas.com
Cc: mgalbraith@suse.de
Cc: sgurrappadi@nvidia.com
Cc: vincent.guittot@linaro.org
Cc: yuyang.du@intel.com
Link: http://lkml.kernel.org/r/1469453670-2660-6-git-send-email-morten.rasmussen@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-18 11:26:53 +02:00
Morten Rasmussen
0e6d2a67a4 sched/core: Remove unnecessary NULL-pointer check
Checking if the sched_domain pointer returned by sd_init() is NULL seems
pointless as sd_init() neither checks if it is valid to begin with nor
set it to NULL.

Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dietmar.eggemann@arm.com
Cc: freedom.tan@mediatek.com
Cc: keita.kobayashi.ym@renesas.com
Cc: mgalbraith@suse.de
Cc: sgurrappadi@nvidia.com
Cc: vincent.guittot@linaro.org
Cc: yuyang.du@intel.com
Link: http://lkml.kernel.org/r/1469453670-2660-5-git-send-email-morten.rasmussen@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-18 11:26:53 +02:00
Peter Zijlstra
94f438c84e sched/core: Clarify SD_flags comment
The SD_flags comment is very terse and doesn't explain why PACKING is
odd.

IIRC the distinction is that the 'normal' ones only describe topology,
while the ASYM_PACKING one also prescribes behaviour. It is odd in the
way that it doesn't only describe things.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Morten Rasmussen <morten.rasmussen@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dietmar.eggemann@arm.com
Cc: freedom.tan@mediatek.com
Cc: keita.kobayashi.ym@renesas.com
Cc: mgalbraith@suse.de
Cc: sgurrappadi@nvidia.com
Cc: vincent.guittot@linaro.org
Cc: yuyang.du@intel.com
Link: http://lkml.kernel.org/r/20160815105459.GS6879@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-18 11:26:52 +02:00
Ingo Molnar
5a96215739 Merge branch 'sched/urgent' into sched/core, to pick up dependencies
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-18 11:20:19 +02:00
Wanpeng Li
03cbc73263 sched/cputime: Resync steal time when guest & host lose sync
Commit:

  5743021831 ("sched/cputime: Count actually elapsed irq & softirq time")

... fixed a bug but also triggered a regression:

On an i5 laptop, 4 pCPUs, 4vCPUs for one full dynticks guest, there are four
CPU hog processes(for loop) running in the guest, I hot-unplug the pCPUs
on host one by one until there is only one left, then observe CPU utilization
via 'top' in the guest, it shows:

  100% st for cpu0(housekeeping)
   75% st for other CPUs (nohz full mode)

However, w/o this commit it shows the correct 75% for all four CPUs.

When a guest is interrupted for a longer amount of time, missed clock ticks
are not redelivered later. Because of that, we should not limit the amount
of steal time accounted to the amount of time that the calling functions
think have passed.

However, the interval returned by account_other_time() is NOT rounded down
to the nearest jiffy, while the base interval in get_vtime_delta() it is
subtracted from is, so the max cputime limit is required to avoid underflow.

This patch fixes the regression by limiting the account_other_time() from
get_vtime_delta() to avoid underflow, and lets the other three call sites
(in account_other_time() and steal_account_process_time()) account however
much steal time the host told us elapsed.

Suggested-by: Rik van Riel <riel@redhat.com>
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Radim Krcmar <rkrcmar@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: kvm@vger.kernel.org
Link: http://lkml.kernel.org/r/1471399546-4069-1-git-send-email-wanpeng.li@hotmail.com
[ Improved the changelog. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-18 11:19:48 +02:00
Rik van Riel
1fc770d589 sched: Remove struct rq::nohz_stamp
The nohz_stamp member of struct rq has been unused since 2010,
when this commit removed the code that referenced it:

  396e894d28 ("sched: Revert nohz_ratelimit() for now")

Signed-off-by: Rik van Riel <riel@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20160815121410.5ea1c98f@annuminas.surriel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-18 10:55:39 +02:00
David Carrillo-Cisneros
d6a2f9035b perf/core: Introduce PMU_EV_CAP_READ_ACTIVE_PKG
Introduce the flag PMU_EV_CAP_READ_ACTIVE_PKG, useful for uncore events,
that allows a PMU to signal the generic perf code that an event is readable
in the current CPU if the event is active in a CPU in the same package as
the current CPU.

This is an optimization that avoids a unnecessary IPI for the common case
where uncore events are run and read in the same package but in
different CPUs.

As an example, the IPI removal speeds up perf_read() in my Haswell system
as follows:

  - For event UNC_C_LLC_LOOKUP: From 260 us to 31 us.
  - For event RAPL's power/energy-cores/: From to 255 us to 27 us.

For the optimization to work, all events in the group must have it
(similarly to PERF_EV_CAP_SOFTWARE).

Signed-off-by: David Carrillo-Cisneros <davidcc@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Carrillo-Cisneros <davidcc@google.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul Turner <pjt@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vegard Nossum <vegard.nossum@gmail.com>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: http://lkml.kernel.org/r/1471467307-61171-4-git-send-email-davidcc@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-18 10:53:59 +02:00
Peter Zijlstra
173be9a14f sched/cputime: Fix NO_HZ_FULL getrusage() monotonicity regression
Mike reports:

 Roughly 10% of the time, ltp testcase getrusage04 fails:
 getrusage04    0  TINFO  :  Expected timers granularity is 4000 us
 getrusage04    0  TINFO  :  Using 1 as multiply factor for max [us]time increment (1000+4000us)!
 getrusage04    0  TINFO  :  utime:           0us; stime:         179us
 getrusage04    0  TINFO  :  utime:        3751us; stime:           0us
 getrusage04    1  TFAIL  :  getrusage04.c:133: stime increased > 5000us:

And tracked it down to the case where the task simply doesn't get
_any_ [us]time ticks.

Update the code to assume all rtime is utime when we lack information,
thus ensuring a task that elides the tick gets time accounted.

Reported-by: Mike Galbraith <umgwanakikbuti@gmail.com>
Tested-by: Mike Galbraith <umgwanakikbuti@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Fredrik Markstrom <fredrik.markstrom@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Radim <rkrcmar@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: Wanpeng Li <wanpeng.li@hotmail.com>
Cc: stable@vger.kernel.org # 4.3+
Fixes: 9d7fb04276 ("sched/cputime: Guarantee stime + utime == rtime")
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-18 10:48:46 +02:00
David Carrillo-Cisneros
4ff6a8debf perf/core: Generalize event->group_flags
Currently, PERF_GROUP_SOFTWARE is used in the group_flags field of a
group's leader to indicate that is_software_event(event) is true for all
events in a group. This is the only usage of event->group_flags.

This pattern of setting a group level flags when all events in the group
share a property is useful for the flag introduced in the next patch and
for future CQM/CMT flags. So this patches generalizes group_flags to work
as an aggregate of event level flags.

PERF_GROUP_SOFTWARE denotes an inmutable event's property. All other flags
that I intend to add are also determinable at event initialization.
To better convey the above, this patch renames event's group_flags to
group_caps and PERF_GROUP_SOFTWARE to PERF_EV_CAP_SOFTWARE.

Individual event flags are stored in the new event->event_caps. Since the
cap flags do not change after event initialization, there is no need to
serialize event_caps. This new field is used when events are added to a
context, similarly to how PERF_GROUP_SOFTWARE and is_software_event()
worked.

Lastly, for consistency, updates is_software_event() to rely in event_cap
instead of the context index.

Signed-off-by: David Carrillo-Cisneros <davidcc@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul Turner <pjt@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vegard Nossum <vegard.nossum@gmail.com>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: http://lkml.kernel.org/r/1471467307-61171-3-git-send-email-davidcc@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-18 10:44:21 +02:00
Madhavan Srinivasan
29dd328870 bitmap.h, perf/core: Fix the mask in perf_output_sample_regs()
When decoding the perf_regs mask in perf_output_sample_regs(),
we loop through the mask using find_first_bit and find_next_bit functions.

While the exisiting code works fine in most of the case, the logic
is broken for big-endian 32-bit kernels.

When reading a u64 mask using (u32 *)(&val)[0], find_*_bit() assumes
that it gets the lower 32 bits of u64, but instead it gets the upper
32 bits - which is wrong.

The fix is to swap the words of the u64 to handle this case.
This is _not_ a regular endianness swap.

Suggested-by: Yury Norov <ynorov@caviumnetworks.com>
Signed-off-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Yury Norov <ynorov@caviumnetworks.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: linuxppc-dev@lists.ozlabs.org
Link: http://lkml.kernel.org/r/1471426568-31051-2-git-send-email-maddy@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-18 10:44:20 +02:00
Ingo Molnar
8942c2b7f3 Merge branch 'perf/urgent' into perf/core, to pick up dependencies
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-18 10:36:21 +02:00
David Carrillo-Cisneros
71e7bc2bab perf/core: Check return value of the perf_event_read() IPI
The call to smp_call_function_single in perf_event_read() may fail if
an invalid or not online CPU index is passed. Warn user if such bug is
present and return error.

Signed-off-by: David Carrillo-Cisneros <davidcc@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul Turner <pjt@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vegard Nossum <vegard.nossum@gmail.com>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: http://lkml.kernel.org/r/1471467307-61171-2-git-send-email-davidcc@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-18 10:35:52 +02:00
Mathieu Poirier
99f5bc9bfa perf/core: Enable mapping of the stop filters
At this time the perf_addr_filter_needs_mmap() function will _not_
return true on a user space 'stop' filter.  But stop filters need
exactly the same kind of mapping that range and start filters get.

Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: http://lkml.kernel.org/r/1468860187-318-4-git-send-email-mathieu.poirier@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-18 10:35:51 +02:00
Mathieu Poirier
12b40a2393 perf/core: Update filters only on executable mmap
Function perf_event_mmap() is called by the MM subsystem each time
part of a binary is loaded in memory.  There can be several mapping
for a binary, many times unrelated to the code section.

Each time a section of a binary is mapped address filters are
updated, event when the map doesn't pertain to the code section.
The end result is that filters are configured based on the last map
event that was received rather than the last mapping of the code
segment.

For example if we have an executable 'main' that calls library
'libcstest.so.1.0', and that we want to collect traces on code
that is in that library.  The perf cmd line for this scenario
would be:

  perf record -e cs_etm// --filter 'filter 0x72c/0x40@/opt/lib/libcstest.so.1.0' --per-thread ./main

Resulting in binaries being mapped this way:

  root@linaro-nano:~# cat /proc/1950/maps
  00400000-00401000 r-xp 00000000 08:02 33169     /home/linaro/main
  00410000-00411000 r--p 00000000 08:02 33169     /home/linaro/main
  00411000-00412000 rw-p 00001000 08:02 33169     /home/linaro/main
  7fa2464000-7fa2474000 rw-p 00000000 00:00 0
  7fa2474000-7fa25a4000 r-xp 00000000 08:02 543   /lib/aarch64-linux-gnu/libc-2.21.so
  7fa25a4000-7fa25b3000 ---p 00130000 08:02 543   /lib/aarch64-linux-gnu/libc-2.21.so
  7fa25b3000-7fa25b7000 r--p 0012f000 08:02 543   /lib/aarch64-linux-gnu/libc-2.21.so
  7fa25b7000-7fa25b9000 rw-p 00133000 08:02 543   /lib/aarch64-linux-gnu/libc-2.21.so
  7fa25b9000-7fa25bd000 rw-p 00000000 00:00 0
  7fa25bd000-7fa25be000 r-xp 00000000 08:02 38308 /opt/lib/libcstest.so.1.0
  7fa25be000-7fa25cd000 ---p 00001000 08:02 38308 /opt/lib/libcstest.so.1.0
  7fa25cd000-7fa25ce000 r--p 00000000 08:02 38308 /opt/lib/libcstest.so.1.0
  7fa25ce000-7fa25cf000 rw-p 00001000 08:02 38308 /opt/lib/libcstest.so.1.0
  7fa25cf000-7fa25eb000 r-xp 00000000 08:02 574   /lib/aarch64-linux-gnu/ld-2.21.so
  7fa25ef000-7fa25f2000 rw-p 00000000 00:00 0
  7fa25f7000-7fa25f9000 rw-p 00000000 00:00 0
  7fa25f9000-7fa25fa000 r--p 00000000 00:00 0     [vvar]
  7fa25fa000-7fa25fb000 r-xp 00000000 00:00 0     [vdso]
  7fa25fb000-7fa25fc000 r--p 0001c000 08:02 574   /lib/aarch64-linux-gnu/ld-2.21.so
  7fa25fc000-7fa25fe000 rw-p 0001d000 08:02 574   /lib/aarch64-linux-gnu/ld-2.21.so
  7ff2ea8000-7ff2ec9000 rw-p 00000000 00:00 0     [stack]
  root@linaro-nano:~#

Before 'main()' can execute 'libcstest.so.1.0' has to be loaded in
memory.  Once that has been done perf_event_mmap() has been called
4 times, with the last map starting at address 0x7fa25ce000 and
the address filter configured to start filtering when the
IP has passed over address 0x0x7fa25ce72c (0x7fa25ce000 + 0x72c).

But that is wrong since the code segment for library 'libcstest.so.1.0'
as been mapped at 0x7fa25bd000, resulting in traces not being
collected.

This patch corrects the situation by requesting that address
filters be updated only if the mapped event is for a code
segment.

Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: http://lkml.kernel.org/r/1468860187-318-3-git-send-email-mathieu.poirier@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-18 10:35:50 +02:00
Mathieu Poirier
4059ffd09d perf/core: Fix file name handling for start/stop filters
Binary file names have to be supplied for both range and start/stop
filters but the current code only processes the filename if an
address range filter is specified.  This code adds processing of
the filename for start/stop filters.

Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: http://lkml.kernel.org/r/1468860187-318-2-git-send-email-mathieu.poirier@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-18 10:35:50 +02:00
Peter Zijlstra
cca2094605 perf/core: Fix event_function_local()
Vincent reported triggering the WARN_ON_ONCE() in event_function_local().

While thinking through cases I noticed that by using event_function()
directly, we miss the inactive case usually handled by
event_function_call().

Therefore construct a blend of event_function_call() and
event_function() that handles the cases relevant to
event_function_local().

Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org # 4.5+
Fixes: fae3fde651 ("perf: Collapse and fix event_function_call() users")
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-18 10:35:49 +02:00
Oleg Nesterov
bdfaa2eecd uprobes: Rename the "struct page *" args of __replace_page()
Purely cosmetic, no changes in the compiled code.

Perhaps it is just me but I can hardly read __replace_page() because I can't
distinguish "page" from "kpage" and because I need to look at the caller to
to ensure that, say, kpage is really the new page and the code is correct.
Rename them to old_page and new_page, this matches the caller.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Brenden Blanco <bblanco@plumgrid.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vladimir Davydov <vdavydov@virtuozzo.com>
Link: http://lkml.kernel.org/r/20160817153704.GC29724@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-18 10:03:50 +02:00
Ingo Molnar
bc06f00dbd Merge branch 'perf/urgent' into perf/core, to pick up dependency
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-18 10:03:35 +02:00
Oleg Nesterov
6c4687cc17 uprobes: Fix the memcg accounting
__replace_page() wronlgy calls mem_cgroup_cancel_charge() in "success" path,
it should only do this if page_check_address() fails.

This means that every enable/disable leads to unbalanced mem_cgroup_uncharge()
from put_page(old_page), it is trivial to underflow the page_counter->count
and trigger OOM.

Reported-and-tested-by: Brenden Blanco <bblanco@plumgrid.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vladimir Davydov <vdavydov@virtuozzo.com>
Cc: stable@vger.kernel.org # 3.17+
Fixes: 00501b531c ("mm: memcontrol: rewrite charge API")
Link: http://lkml.kernel.org/r/20160817153629.GB29724@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-18 10:03:26 +02:00
David S. Miller
60747ef4d1 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Minor overlapping changes for both merge conflicts.

Resolution work done by Stephen Rothwell was used
as a reference.

Signed-off-by: David S. Miller <davem@davemloft.net>
2016-08-18 01:17:32 -04:00
Rafael J. Wysocki
6c16f42a4e Merge branch 'pm-sleep'
* pm-sleep:
  PM / hibernate: Fix rtree_next_node() to avoid walking off list ends
  x86/power/64: Use __pa() for physical address computation
  PM / sleep: Update some system sleep documentation
2016-08-18 03:27:08 +02:00
Linus Torvalds
184ca82348 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Pull networking fixes from David Miller:

 1) Buffers powersave frame test is reversed in cfg80211, fix from Felix
    Fietkau.

 2) Remove bogus WARN_ON in openvswitch, from Jarno Rajahalme.

 3) Fix some tg3 ethtool logic bugs, and one that would cause no
    interrupts to be generated when rx-coalescing is set to 0.  From
    Satish Baddipadige and Siva Reddy Kallam.

 4) QLCNIC mailbox corruption and napi budget handling fix from Manish
    Chopra.

 5) Fix fib_trie logic when walking the trie during /proc/net/route
    output than can access a stale node pointer.  From David Forster.

 6) Several sctp_diag fixes from Phil Sutter.

 7) PAUSE frame handling fixes in mlxsw driver from Ido Schimmel.

 8) Checksum fixup fixes in bpf from Daniel Borkmann.

 9) Memork leaks in nfnetlink, from Liping Zhang.

10) Use after free in rxrpc, from David Howells.

11) Use after free in new skb_array code of macvtap driver, from Jason
    Wang.

12) Calipso resource leak, from Colin Ian King.

13) mediatek bug fixes (missing stats sync init, etc.) from Sean Wang.

14) Fix bpf non-linear packet write helpers, from Daniel Borkmann.

15) Fix lockdep splats in macsec, from Sabrina Dubroca.

16) hv_netvsc bug fixes from Vitaly Kuznetsov, mostly to do with VF
    handling.

17) Various tc-action bug fixes, from CONG Wang.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (116 commits)
  net_sched: allow flushing tc police actions
  net_sched: unify the init logic for act_police
  net_sched: convert tcf_exts from list to pointer array
  net_sched: move tc offload macros to pkt_cls.h
  net_sched: fix a typo in tc_for_each_action()
  net_sched: remove an unnecessary list_del()
  net_sched: remove the leftover cleanup_a()
  mlxsw: spectrum: Allow packets to be trapped from any PG
  mlxsw: spectrum: Unmap 802.1Q FID before destroying it
  mlxsw: spectrum: Add missing rollbacks in error path
  mlxsw: reg: Fix missing op field fill-up
  mlxsw: spectrum: Trap loop-backed packets
  mlxsw: spectrum: Add missing packet traps
  mlxsw: spectrum: Mark port as active before registering it
  mlxsw: spectrum: Create PVID vPort before registering netdevice
  mlxsw: spectrum: Remove redundant errors from the code
  mlxsw: spectrum: Don't return upon error in removal path
  i40e: check for and deal with non-contiguous TCs
  ixgbe: Re-enable ability to toggle VLAN filtering
  ixgbe: Force VLNCTRL.VFE to be set in all VMDq paths
  ...
2016-08-17 17:26:58 -07:00
Balbir Singh
568ac88821 cgroup: reduce read locked section of cgroup_threadgroup_rwsem during fork
cgroup_threadgroup_rwsem is acquired in read mode during process exit
and fork.  It is also grabbed in write mode during
__cgroups_proc_write().  I've recently run into a scenario with lots
of memory pressure and OOM and I am beginning to see

systemd

 __switch_to+0x1f8/0x350
 __schedule+0x30c/0x990
 schedule+0x48/0xc0
 percpu_down_write+0x114/0x170
 __cgroup_procs_write.isra.12+0xb8/0x3c0
 cgroup_file_write+0x74/0x1a0
 kernfs_fop_write+0x188/0x200
 __vfs_write+0x6c/0xe0
 vfs_write+0xc0/0x230
 SyS_write+0x6c/0x110
 system_call+0x38/0xb4

This thread is waiting on the reader of cgroup_threadgroup_rwsem to
exit.  The reader itself is under memory pressure and has gone into
reclaim after fork. There are times the reader also ends up waiting on
oom_lock as well.

 __switch_to+0x1f8/0x350
 __schedule+0x30c/0x990
 schedule+0x48/0xc0
 jbd2_log_wait_commit+0xd4/0x180
 ext4_evict_inode+0x88/0x5c0
 evict+0xf8/0x2a0
 dispose_list+0x50/0x80
 prune_icache_sb+0x6c/0x90
 super_cache_scan+0x190/0x210
 shrink_slab.part.15+0x22c/0x4c0
 shrink_zone+0x288/0x3c0
 do_try_to_free_pages+0x1dc/0x590
 try_to_free_pages+0xdc/0x260
 __alloc_pages_nodemask+0x72c/0xc90
 alloc_pages_current+0xb4/0x1a0
 page_table_alloc+0xc0/0x170
 __pte_alloc+0x58/0x1f0
 copy_page_range+0x4ec/0x950
 copy_process.isra.5+0x15a0/0x1870
 _do_fork+0xa8/0x4b0
 ppc_clone+0x8/0xc

In the meanwhile, all processes exiting/forking are blocked almost
stalling the system.

This patch moves the threadgroup_change_begin from before
cgroup_fork() to just before cgroup_canfork().  There is no nee to
worry about threadgroup changes till the task is actually added to the
threadgroup.  This avoids having to call reclaim with
cgroup_threadgroup_rwsem held.

tj: Subject and description edits.

Signed-off-by: Balbir Singh <bsingharora@gmail.com>
Acked-by: Zefan Li <lizefan@huawei.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: stable@vger.kernel.org # v4.2+
Signed-off-by: Tejun Heo <tj@kernel.org>
2016-08-17 09:54:52 -04:00
Marc Zyngier
1e12c4a939 genirq: Correctly configure the trigger on chained interrupts
Commit 1e2a7d7849 ("irqdomain: Don't set type when mapping an IRQ")
moved the trigger configuration call from the irqdomain mapping to
the interrupt being actually requested.

This patch failed to handle the case where we configure a chained
interrupt, which doesn't get requested through the usual path.

In order to solve this, let's call __irq_set_trigger just before
starting the cascade interrupt. Special care must be taken to
make the flow handler stick, as the .irq_set_type method could
have reset it (it doesn't know we're dealing with a chained
interrupt).

Based on an initial patch by Jon Hunter.

Fixes: 1e2a7d7849 ("irqdomain: Don't set type when mapping an IRQ")
Reported-by: John Stultz <john.stultz@linaro.org>
Reported-by: Linus Walleij <linus.walleij@linaro.org>
Tested-by: John Stultz <john.stultz@linaro.org>
Acked-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2016-08-17 11:29:31 +01:00
Rafael J. Wysocki
12bde33dbb cpufreq / sched: Pass runqueue pointer to cpufreq_update_util()
All of the callers of cpufreq_update_util() pass rq_clock(rq) to it
as the time argument and some of them check whether or not cpu_of(rq)
is equal to smp_processor_id() before calling it, so rework it to
take a runqueue pointer as the argument and move the rq_clock(rq)
evaluation into it.

Additionally, provide a wrapper checking cpu_of(rq) against
smp_processor_id() for the cpufreq_update_util() callers that
need it.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
2016-08-16 22:16:03 +02:00
Rafael J. Wysocki
58919e83c8 cpufreq / sched: Pass flags to cpufreq_update_util()
It is useful to know the reason why cpufreq_update_util() has just
been called and that can be passed as flags to cpufreq_update_util()
and to the ->func() callback in struct update_util_data.  However,
doing that in addition to passing the util and max arguments they
already take would be clumsy, so avoid it.

Instead, use the observation that the schedutil governor is part
of the scheduler proper, so it can access scheduler data directly.
This allows the util and max arguments of cpufreq_update_util()
and the ->func() callback in struct update_util_data to be replaced
with a flags one, but schedutil has to be modified to follow.

Thus make the schedutil governor obtain the CFS utilization
information from the scheduler and use the "RT" and "DL" flags
instead of the special utilization value of ULONG_MAX to track
updates from the RT and DL sched classes.  Make it non-modular
too to avoid having to export scheduler variables to modules at
large.

Next, update all of the other users of cpufreq_update_util()
and the ->func() callback in struct update_util_data accordingly.

Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
2016-08-16 22:14:55 +02:00
Adrian Hunter
7afafc8a44 block: Fix secure erase
Commit 288dab8a35 ("block: add a separate operation type for secure
erase") split REQ_OP_SECURE_ERASE from REQ_OP_DISCARD without considering
all the places REQ_OP_DISCARD was being used to mean either. Fix those.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Fixes: 288dab8a35 ("block: add a separate operation type for secure erase")
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-08-16 09:16:51 -06:00
James Morse
924d869675 PM / hibernate: Fix rtree_next_node() to avoid walking off list ends
rtree_next_node() walks the linked list of leaf nodes to find the next
block of pages in the struct memory_bitmap. If it walks off the end of
the list of nodes, it walks the list of memory zones to find the next
region of memory. If it walks off the end of the list of zones, it
returns false.

This leaves the struct bm_position's node and zone pointers pointing
at their respective struct list_heads in struct mem_zone_bm_rtree.

memory_bm_find_bit() uses struct bm_position's node and zone pointers
to avoid walking lists and trees if the next bit appears in the same
node/zone. It handles these values being stale.

Swap rtree_next_node()s 'step then test' to 'test-next then step',
this means if we reach the end of memory we return false and leave
the node and zone pointers as they were.

This fixes a panic on resume using AMD Seattle with 64K pages:
[    6.868732] Freezing user space processes ... (elapsed 0.000 seconds) done.
[    6.875753] Double checking all user space processes after OOM killer disable... (elapsed 0.000 seconds)
[    6.896453] PM: Using 3 thread(s) for decompression.
[    6.896453] PM: Loading and decompressing image data (5339 pages)...
[    7.318890] PM: Image loading progress:   0%
[    7.323395] Unable to handle kernel paging request at virtual address 00800040
[    7.330611] pgd = ffff000008df0000
[    7.334003] [00800040] *pgd=00000083fffe0003, *pud=00000083fffe0003, *pmd=00000083fffd0003, *pte=0000000000000000
[    7.344266] Internal error: Oops: 96000005 [#1] PREEMPT SMP
[    7.349825] Modules linked in:
[    7.352871] CPU: 2 PID: 1 Comm: swapper/0 Tainted: G        W I     4.8.0-rc1 #4737
[    7.360512] Hardware name: AMD Overdrive/Supercharger/Default string, BIOS ROD1002C 04/08/2016
[    7.369109] task: ffff8003c0220000 task.stack: ffff8003c0280000
[    7.375020] PC is at set_bit+0x18/0x30
[    7.378758] LR is at memory_bm_set_bit+0x24/0x30
[    7.383362] pc : [<ffff00000835bbc8>] lr : [<ffff0000080faf18>] pstate: 60000045
[    7.390743] sp : ffff8003c0283b00
[    7.473551]
[    7.475031] Process swapper/0 (pid: 1, stack limit = 0xffff8003c0280020)
[    7.481718] Stack: (0xffff8003c0283b00 to 0xffff8003c0284000)
[    7.800075] Call trace:
[    7.887097] [<ffff00000835bbc8>] set_bit+0x18/0x30
[    7.891876] [<ffff0000080fb038>] duplicate_memory_bitmap.constprop.38+0x54/0x70
[    7.899172] [<ffff0000080fcc40>] snapshot_write_next+0x22c/0x47c
[    7.905166] [<ffff0000080fe1b4>] load_image_lzo+0x754/0xa88
[    7.910725] [<ffff0000080ff0a8>] swsusp_read+0x144/0x230
[    7.916025] [<ffff0000080fa338>] load_image_and_restore+0x58/0x90
[    7.922105] [<ffff0000080fa660>] software_resume+0x2f0/0x338
[    7.927752] [<ffff000008083350>] do_one_initcall+0x38/0x11c
[    7.933314] [<ffff000008b40cc0>] kernel_init_freeable+0x14c/0x1ec
[    7.939395] [<ffff0000087ce564>] kernel_init+0x10/0xfc
[    7.944520] [<ffff000008082e90>] ret_from_fork+0x10/0x40
[    7.949820] Code: d2800022 8b400c21 f9800031 9ac32043 (c85f7c22)
[    7.955909] ---[ end trace 0024a5986e6ff323 ]---
[    7.960529] Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b

Here struct mem_zone_bm_rtree's start_pfn has been returned instead of
struct rtree_node's addr as the node/zone pointers are corrupt after
we walked off the end of the lists during mark_unsafe_pages().

This behaviour was exposed by commit 6dbecfd345 ("PM / hibernate:
Simplify mark_unsafe_pages()"), which caused mark_unsafe_pages() to call
duplicate_memory_bitmap(), which uses memory_bm_find_bit() after walking
off the end of the memory bitmap.

Fixes: 3a20cb1779 (PM / Hibernate: Implement position keeping in radix tree)
Signed-off-by: James Morse <james.morse@arm.com>
[ rjw: Subject ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2016-08-16 13:16:36 +02:00
Alexei Starovoitov
8937bd80fc bpf: allow bpf_get_prandom_u32() to be used in tracing
bpf_get_prandom_u32() was initially introduced for socket filters
and later requested numberous times to be added to tracing bpf programs
for the same reason as in socket filters: to be able to randomly
select incoming events.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-08-12 21:57:05 -07:00
Alexei Starovoitov
6841de8b0d bpf: allow helpers access the packet directly
The helper functions like bpf_map_lookup_elem(map, key) were only
allowing 'key' to point to the initialized stack area.
That is causing performance degradation when programs need to process
millions of packets per second and need to copy contents of the packet
into the stack just to pass the stack pointer into the lookup() function.
Allow such helpers read from the packet directly.
All helpers that expect ARG_PTR_TO_MAP_KEY, ARG_PTR_TO_MAP_VALUE,
ARG_PTR_TO_STACK assume byte aligned pointer, so no alignment concerns,
only need to check that helper will not be accessing beyond
the packet range verified by the prior 'if (ptr < data_end)' condition.
For now allow this feature for XDP programs only. Later it can be
relaxed for the clsact programs as well.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-08-12 21:56:18 -07:00
Daniel Borkmann
747ea55e4f bpf: fix bpf_skb_in_cgroup helper naming
While hashing out BPF's current_task_under_cgroup helper bits, it came
to discussion that the skb_in_cgroup helper name was suboptimally chosen.

Tejun says:

  So, I think in_cgroup should mean that the object is in that
  particular cgroup while under_cgroup in the subhierarchy of that
  cgroup. Let's rename the other subhierarchy test to under too. I
  think that'd be a lot less confusing going forward.

  [...]

  It's more intuitive and gives us the room to implement the real
  "in" test if ever necessary in the future.

Since this touches uapi bits, we need to change this as long as v4.8
is not yet officially released. Thus, change the helper enum and rename
related bits.

Fixes: 4a482f34af ("cgroup: bpf: Add bpf_skb_in_cgroup_proto")
Reference: http://patchwork.ozlabs.org/patch/658500/
Suggested-by: Sargun Dhillon <sargun@sargun.me>
Suggested-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
2016-08-12 21:53:33 -07:00
Sargun Dhillon
60d20f9195 bpf: Add bpf_current_task_under_cgroup helper
This adds a bpf helper that's similar to the skb_in_cgroup helper to check
whether the probe is currently executing in the context of a specific
subset of the cgroupsv2 hierarchy. It does this based on membership test
for a cgroup arraymap. It is invalid to call this in an interrupt, and
it'll return an error. The helper is primarily to be used in debugging
activities for containers, where you may have multiple programs running in
a given top-level "container".

Signed-off-by: Sargun Dhillon <sargun@sargun.me>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Tejun Heo <tj@kernel.org>
Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-08-12 21:49:41 -07:00
Linus Torvalds
9710cb6624 Power management fixes for v4.8-rc2
- Fix the x86 identity mapping creation helpers to avoid the
    assumption that the base address of the mapping will always be
    aligned at the PGD level, as it may be aligned at the PUD level
    if address space randomization is enabled (Rafael Wysocki).
 
  - Fix the hibernation core to avoid executing tracing functions
    before restoring the processor state completely during resume
    (Thomas Garnier).
 
  - Fix a recently introduced regression in the powernv cpufreq
    driver that causes it to crash due to an out-of-bounds array
    access (Akshay Adiga).
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Merge tag 'pm-4.8-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull power management fixes from Rafael Wysocki:
 "Two hibernation fixes allowing it to work with the recently added
  randomization of the kernel identity mapping base on x86-64 and one
  cpufreq driver regression fix.

  Specifics:

   - Fix the x86 identity mapping creation helpers to avoid the
     assumption that the base address of the mapping will always be
     aligned at the PGD level, as it may be aligned at the PUD level if
     address space randomization is enabled (Rafael Wysocki).

   - Fix the hibernation core to avoid executing tracing functions
     before restoring the processor state completely during resume
     (Thomas Garnier).

   - Fix a recently introduced regression in the powernv cpufreq driver
     that causes it to crash due to an out-of-bounds array access
     (Akshay Adiga)"

* tag 'pm-4.8-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  PM / hibernate: Restore processor state before using per-CPU variables
  x86/power/64: Always create temporary identity mapping correctly
  cpufreq: powernv: Fix crash in gpstate_timer_handler()
2016-08-12 16:23:58 -07:00
Linus Torvalds
3bc6d8c155 Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer fixes from Ingo Molnar:
 "Misc fixes: a /dev/rtc regression fix, two APIC timer period
  calibration fixes, an ARM clocksource driver fix and a NOHZ
  power use regression fix"

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/hpet: Fix /dev/rtc breakage caused by RTC cleanup
  x86/timers/apic: Inform TSC deadline clockevent device about recalibration
  x86/timers/apic: Fix imprecise timer interrupts by eliminating TSC clockevents frequency roundoff error
  timers: Fix get_next_timer_interrupt() computation
  clocksource/arm_arch_timer: Force per-CPU interrupt to be level-triggered
2016-08-12 13:55:06 -07:00
Rafael J. Wysocki
0aeeb3e73f Merge branches 'pm-sleep' and 'pm-cpufreq'
* pm-sleep:
  PM / hibernate: Restore processor state before using per-CPU variables
  x86/power/64: Always create temporary identity mapping correctly

* pm-cpufreq:
  cpufreq: powernv: Fix crash in gpstate_timer_handler()
2016-08-12 22:53:58 +02:00
Linus Torvalds
e6e7214fbb Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler fixes from Ingo Molnar:
 "Misc fixes: cputime fixes, two deadline scheduler fixes and a cgroups
  scheduling fix"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/cputime: Fix omitted ticks passed in parameter
  sched/cputime: Fix steal time accounting
  sched/deadline: Fix lock pinning warning during CPU hotplug
  sched/cputime: Mitigate performance regression in times()/clock_gettime()
  sched/fair: Fix typo in sync_throttle()
  sched/deadline: Fix wrap-around in DL heap
2016-08-12 13:51:52 -07:00
Thomas Garnier
62822e2ec4 PM / hibernate: Restore processor state before using per-CPU variables
Restore the processor state before calling any other functions to
ensure per-CPU variables can be used with KASLR memory randomization.

Tracing functions use per-CPU variables (GS based on x86) and one was
called just before restoring the processor state fully. It resulted
in a double fault when both the tracing & the exception handler
functions tried to use a per-CPU variable.

Fixes: bb3632c610 (PM / sleep: trace events for suspend/resume)
Reported-and-tested-by: Borislav Petkov <bp@suse.de>
Reported-by: Jiri Kosina <jikos@kernel.org>
Tested-by: Rafael J. Wysocki <rafael@kernel.org>
Tested-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Thomas Garnier <thgarnie@google.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2016-08-12 22:50:42 +02:00
Linus Torvalds
ad83242a8f Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf fixes from Ingo Molnar:
 "Mostly tooling fixes, plus two uncore-PMU fixes, an uprobes fix, a
  perf-cgroups fix and an AUX events fix"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/x86/intel/uncore: Add enable_box for client MSR uncore
  perf/x86/intel/uncore: Fix uncore num_counters
  uprobes/x86: Fix RIP-relative handling of EVEX-encoded instructions
  perf/core: Set cgroup in CPU contexts for new cgroup events
  perf/core: Fix sideband list-iteration vs. event ordering NULL pointer deference crash
  perf probe ppc64le: Fix probe location when using DWARF
  perf probe: Add function to post process kernel trace events
  tools: Sync cpufeatures headers with the kernel
  toops: Sync tools/include/uapi/linux/bpf.h with the kernel
  tools: Sync cpufeatures.h and vmx.h with the kernel
  perf probe: Support signedness casting
  perf stat: Avoid skew when reading events
  perf probe: Fix module name matching
  perf probe: Adjust map->reloc offset when finding kernel symbol from map
  perf hists: Trim libtraceevent trace_seq buffers
  perf script: Add 'bpf-output' field to usage message
2016-08-12 13:21:18 -07:00
Linus Torvalds
1f8083c640 Merge branch 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking fixes from Ingo Molnar:
 "Misc fixes: lockstat fix, futex fix on !MMU systems, big endian fix
  for qrwlocks and a race fix for pvqspinlocks"

* 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  locking/pvqspinlock: Fix a bug in qstat_read()
  locking/pvqspinlock: Fix double hash race
  locking/qrwlock: Fix write unlock bug on big endian systems
  futex: Assume all mappings are private on !MMU systems
2016-08-12 12:46:37 -07:00
Linus Torvalds
25db69188e Merge branch 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull irq fix from Ingo Molnar:
 "A fix for an MSI regression"

* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  genirq/msi: Make sure PCI MSIs are activated early
2016-08-12 12:41:51 -07:00
Frederic Weisbecker
26f2c75cd2 sched/cputime: Fix omitted ticks passed in parameter
Commit:

  f9bcf1e0e0 ("sched/cputime: Fix steal time accounting")

... fixes a leak on steal time accounting but forgets to account
the ticks passed in parameters, assuming there is only one to
take into account.

Let's consider that parameter back.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Wanpeng Li <kernellwp@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Radim <rkrcmar@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Wanpeng Li <wanpeng.li@hotmail.com>
Cc: linux-tip-commits@vger.kernel.org
Link: http://lkml.kernel.org/r/20160811125822.GB4214@lerouge
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-11 16:34:37 +02:00
Wanpeng Li
f9bcf1e0e0 sched/cputime: Fix steal time accounting
Commit:

  5743021831 ("sched/cputime: Count actually elapsed irq & softirq time")

... didn't take steal time into consideration with passing the noirqtime
kernel parameter.

As Paolo pointed out before:

| Why not? If idle=poll, for example, any time the guest is suspended (and
| thus cannot poll) does count as stolen time.

This patch fixes it by reducing steal time from idle time accounting when
the noirqtime parameter is true. The average idle time drops from 56.8%
to 54.75% for nohz idle kvm guest(noirqtime, idle=poll, four vCPUs running
on one pCPU).

Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Radim <rkrcmar@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1470893795-3527-1-git-send-email-wanpeng.li@hotmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-11 11:02:14 +02:00
Vegard Nossum
f0b22e39e3 sched/debug: Add taint on "BUG: Sleeping function called from invalid context"
Seeing this, it occurs to me that we should probably add a taint here:

    BUG: sleeping function called from invalid context at mm/slab.h:388
    in_atomic(): 0, irqs_disabled(): 0, pid: 32211, name: trinity-c3
    Preemption disabled at:[<ffffffff811aaa37>] console_unlock+0x2f7/0x930

    CPU: 3 PID: 32211 Comm: trinity-c3 Not tainted 4.7.0-rc7+ #19
                                       ^^^^^^^^^^^
    Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014
     0000000000000000 ffff8800b8a17160 ffffffff81971441 ffff88011a3c4c80
     ffff88011a3c4c80 ffff8800b8a17198 ffffffff81158067 0000000000000de6
     ffff88011a3c4c80 ffffffff8390e07c 0000000000000184 0000000000000000
    Call Trace:
    [...]

    BUG: sleeping function called from invalid context at arch/x86/mm/fault.c:1309
    in_atomic(): 0, irqs_disabled(): 0, pid: 32211, name: trinity-c3
    Preemption disabled at:[<ffffffff8119db33>] down_trylock+0x13/0x80

    CPU: 3 PID: 32211 Comm: trinity-c3 Not tainted 4.7.0-rc7+ #19
                                       ^^^^^^^^^^^
    Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014
     0000000000000000 ffff8800b8a17e08 ffffffff81971441 ffff88011a3c4c80
     ffff88011a3c4c80 ffff8800b8a17e40 ffffffff81158067 0000000000000000
     ffff88011a3c4c80 ffffffff83437b20 000000000000051d 0000000000000000
    Call Trace:
    [...]

Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rusty Russel <rusty@rustcorp.com.au>
Link: http://lkml.kernel.org/r/1469216762-19626-1-git-send-email-vegard.nossum@oracle.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-10 16:13:48 +02:00
Vegard Nossum
d1c6d149cf sched/debug: Make the "Preemption disabled at ..." message more useful
This message is currently really useless since it always prints a value
that comes from the printk() we just did, e.g.:

    BUG: sleeping function called from invalid context at mm/slab.h:388
    in_atomic(): 0, irqs_disabled(): 0, pid: 31996, name: trinity-c1
    Preemption disabled at:[<ffffffff8119db33>] down_trylock+0x13/0x80

    BUG: sleeping function called from invalid context at include/linux/freezer.h:56
    in_atomic(): 0, irqs_disabled(): 0, pid: 31996, name: trinity-c1
    Preemption disabled at:[<ffffffff811aaa37>] console_unlock+0x2f7/0x930

Here, both down_trylock() and console_unlock() is somewhere in the
printk() path.

We should save the value before calling printk() and use the saved value
instead. That immediately reveals the offending callsite:

    BUG: sleeping function called from invalid context at mm/slab.h:388
    in_atomic(): 0, irqs_disabled(): 0, pid: 14971, name: trinity-c2
    Preemption disabled at:[<ffffffff819bcd46>] rhashtable_walk_start+0x46/0x150

Bug report:

  http://marc.info/?l=linux-netdev&m=146925979821849&w=2

Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rusty Russel <rusty@rustcorp.com.au>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-10 16:07:20 +02:00
Boris Ostrovsky
aa877175e7 cpu/hotplug: Prevent alloc/free of irq descriptors during CPU up/down (again)
Now that Xen no longer allocates irqs in _cpu_up() we can restore
commit:

  a899418167 ("hotplug: Prevent alloc/free of irq descriptors during cpu up/down")

Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Anna-Maria Gleixner <anna-maria@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: david.vrabel@citrix.com
Cc: xen-devel@lists.xenproject.org
Link: http://lkml.kernel.org/r/1470244948-17674-3-git-send-email-boris.ostrovsky@oracle.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-10 15:42:57 +02:00
Ingo Molnar
fdbdfefbab Merge branch 'linus' into timers/urgent, to pick up fixes
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-10 14:36:23 +02:00
Peter Zijlstra
80127a3968 locking/percpu-rwsem: Optimize readers and reduce global impact
Currently the percpu-rwsem switches to (global) atomic ops while a
writer is waiting; which could be quite a while and slows down
releasing the readers.

This patch cures this problem by ordering the reader-state vs
reader-count (see the comments in __percpu_down_read() and
percpu_down_write()). This changes a global atomic op into a full
memory barrier, which doesn't have the global cacheline contention.

This also enables using the percpu-rwsem with rcu_sync disabled in order
to bias the implementation differently, reducing the writer latency by
adding some cost to readers.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
[ Fixed modular build. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-10 14:34:01 +02:00
Waiman Long
08be8f63c4 locking/pvstat: Separate wait_again and spurious wakeup stats
Currently there are overlap in the pvqspinlock wait_again and
spurious_wakeup stat counters. Because of lock stealing, it is
no longer possible to accurately determine if spurious wakeup has
happened in the queue head.  As they track both the queue node and
queue head status, it is also hard to tell how many of those comes
from the queue head and how many from the queue node.

This patch changes the accounting rules so that spurious wakeup is
only tracked in the queue node. The wait_again count, however, is
only tracked in the queue head when the vCPU failed to acquire the
lock after a vCPU kick. This should give a much better indication of
the wait-kick dynamics in the queue node and the queue head.

Signed-off-by: Waiman Long <Waiman.Long@hpe.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Douglas Hatch <doug.hatch@hpe.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Pan Xinhui <xinhui@linux.vnet.ibm.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Scott J Norton <scott.norton@hpe.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1464713631-1066-2-git-send-email-Waiman.Long@hpe.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-10 14:16:02 +02:00
Peter Zijlstra
64a5e3cb30 locking/qspinlock: Improve readability
Restructure pv_queued_spin_steal_lock() as I found it hard to read.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Waiman Long <waiman.long@hpe.com
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-10 14:16:02 +02:00
Pan Xinhui
c2ace36b88 locking/pvqspinlock: Fix a bug in qstat_read()
It's obviously wrong to set stat to NULL. So lets remove it.
Otherwise it is always zero when we check the latency of kick/wake.

Signed-off-by: Pan Xinhui <xinhui.pan@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Waiman Long <Waiman.Long@hpe.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1468405414-3700-1-git-send-email-xinhui.pan@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-10 14:13:29 +02:00
Wanpeng Li
229ce63157 locking/pvqspinlock: Fix double hash race
When the lock holder vCPU is racing with the queue head:

   CPU 0 (lock holder)    CPU1 (queue head)
   ===================    =================
   spin_lock();           spin_lock();
    pv_kick_node():        pv_wait_head_or_lock():
                            if (!lp) {
                             lp = pv_hash(lock, pn);
                             xchg(&l->locked, _Q_SLOW_VAL);
                            }
                            WRITE_ONCE(pn->state, vcpu_halted);
     cmpxchg(&pn->state,
      vcpu_halted, vcpu_hashed);
     WRITE_ONCE(l->locked, _Q_SLOW_VAL);
     (void)pv_hash(lock, pn);

In this case, lock holder inserts the pv_node of queue head into the
hash table and set _Q_SLOW_VAL unnecessary. This patch avoids it by
restoring/setting vcpu_hashed state after failing adaptive locking
spinning.

Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Pan Xinhui <xinhui.pan@linux.vnet.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Waiman Long <Waiman.Long@hpe.com>
Link: http://lkml.kernel.org/r/1468484156-4521-1-git-send-email-wanpeng.li@hotmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-10 14:13:28 +02:00
Ingo Molnar
a2071cd765 Merge branch 'linus' into locking/urgent, to pick up fixes
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-10 14:11:54 +02:00
Juri Lelli
98b0a85780 sched/deadline: Remove useless parameter from setup_new_dl_entity()
setup_new_dl_entity() takes two parameters, but it only actually uses
one of them, under a different name, to setup a new dl_entity, after:

  2f9f3fdc928 "sched/deadline: Remove dl_new from struct sched_dl_entity"

as we currently do:

  setup_new_dl_entity(&p->dl, &p->dl)

However, before Luca's change we were doing:

  setup_new_dl_entity(dl_se, pi_se)

in update_dl_entity() for a dl_se->new entity: we were using pi_se's
parameters (the potential PI donor) for setting up a new entity.

This change removes the useless second parameter of setup_new_dl_entity().

While we are at it we also optimize things further calling setup_new_dl_
entity() only for already queued tasks, since (as pointed out by Xunlei)
we already do the very same update at tasks wakeup time anyway. By doing
so, we don't need to worry about a potential PI donor anymore, as
rt_mutex_setprio() takes care of that already for us.

Signed-off-by: Juri Lelli <juri.lelli@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luca Abeni <luca.abeni@unitn.it>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Xunlei Pang <xpang@redhat.com>
Link: http://lkml.kernel.org/r/1470409675-20935-1-git-send-email-juri.lelli@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-10 14:03:32 +02:00
Luis de Bethencourt
9279e0d2e5 sched/core: Add documentation for 'cookie' argument
Add documentation for the cookie argument in try_to_wake_up_local().

This caused the following warning when building documentation:

  kernel/sched/core.c:2088: warning: No description found for parameter 'cookie'

Signed-off-by: Luis de Bethencourt <luisbg@osg.samsung.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: akpm@linux-foundation.org
Fixes: e7904a28f5 ("ilocking/lockdep, sched/core: Implement a better lock pinning scheme")
Link: http://lkml.kernel.org/r/1468159226-17674-1-git-send-email-luisbg@osg.samsung.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-10 14:03:32 +02:00
Morten Rasmussen
eaecf41f5a sched/fair: Optimize find_idlest_cpu() when there is no choice
In the current find_idlest_group()/find_idlest_cpu() search we end up
calling find_idlest_cpu() in a sched_group containing only one CPU in
the end. Checking idle-states becomes pointless when there is no
alternative, so bail out instead.

Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dietmar.eggemann@arm.com
Cc: linux-kernel@vger.kernel.org
Cc: mgalbraith@suse.de
Cc: vincent.guittot@linaro.org
Cc: yuyang.du@intel.com
Link: http://lkml.kernel.org/r/1466615004-3503-4-git-send-email-morten.rasmussen@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-10 14:03:32 +02:00
Morten Rasmussen
772bd008cd sched/fair: Make the use of prev_cpu consistent in the wakeup path
In commit:

  ac66f54772 ("sched/numa: Introduce migrate_swap()")

select_task_rq() got a 'cpu' argument to enable overriding of prev_cpu
in special cases (NUMA task swapping).

However, the select_task_rq_fair() helper functions: wake_affine() and
select_idle_sibling(), still use task_cpu(p) directly to work out
prev_cpu, which leads to inconsistencies.

This patch passes prev_cpu (potentially overridden by NUMA code) into
the helper functions to ensure prev_cpu is indeed the same CPU
everywhere in the wakeup path.

cc: Ingo Molnar <mingo@redhat.com>
cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dietmar.eggemann@arm.com
Cc: linux-kernel@vger.kernel.org
Cc: mgalbraith@suse.de
Cc: vincent.guittot@linaro.org
Cc: yuyang.du@intel.com
Link: http://lkml.kernel.org/r/1466615004-3503-3-git-send-email-morten.rasmussen@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-10 14:03:32 +02:00
Peter Zijlstra
7c3edd2c30 sched/fair: Improve PELT stuff some more
Vincent noted that the update_tg_load_avg() usage in commit:

  3d30544f02 ("sched/fair: Apply more PELT fixes")

isn't entirely sufficient. We need to call this function every time
cfs_rq->avg.load changes, this includes when update_cfs_rq_load_avg()
returns true, but {attach,detach}_entity_load_avg() themselves also
change it. This means we need to unconditionally call
update_tg_load_avg().

Also, add more comments.

Reported-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-10 14:03:32 +02:00
Leo Yan
a1fd46565b sched/core: Fix one typo
Fix one minor typo in the comment: s/targer/target/.

Signed-off-by: Leo Yan <leo.yan@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Link: http://lkml.kernel.org/r/1470378758-15066-1-git-send-email-leo.yan@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-10 14:03:32 +02:00
Leo Yan
31851a9874 sched/fair: Remove 'cpu_busy' parameter from update_next_balance()
The update_next_balance() function is only used by idle balancing, so its
'cpu_busy' parameter is always 0.

Open code it instead of passing it around.

Signed-off-by: Leo Yan <leo.yan@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Link: http://lkml.kernel.org/r/1470378689-14892-1-git-send-email-leo.yan@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-10 14:03:32 +02:00
Wanpeng Li
c0c8c9fa21 sched/deadline: Fix lock pinning warning during CPU hotplug
The following warning can be triggered by hot-unplugging the CPU
on which an active SCHED_DEADLINE task is running on:

  WARNING: CPU: 0 PID: 0 at kernel/locking/lockdep.c:3531 lock_release+0x690/0x6a0
  releasing a pinned lock
  Call Trace:
   dump_stack+0x99/0xd0
   __warn+0xd1/0xf0
   ? dl_task_timer+0x1a1/0x2b0
   warn_slowpath_fmt+0x4f/0x60
   ? sched_clock+0x13/0x20
   lock_release+0x690/0x6a0
   ? enqueue_pushable_dl_task+0x9b/0xa0
   ? enqueue_task_dl+0x1ca/0x480
   _raw_spin_unlock+0x1f/0x40
   dl_task_timer+0x1a1/0x2b0
   ? push_dl_task.part.31+0x190/0x190
  WARNING: CPU: 0 PID: 0 at kernel/locking/lockdep.c:3649 lock_unpin_lock+0x181/0x1a0
  unpinning an unpinned lock
  Call Trace:
   dump_stack+0x99/0xd0
   __warn+0xd1/0xf0
   warn_slowpath_fmt+0x4f/0x60
   lock_unpin_lock+0x181/0x1a0
   dl_task_timer+0x127/0x2b0
   ? push_dl_task.part.31+0x190/0x190

As per the comment before this code, its safe to drop the RQ lock
here, and since we (potentially) change rq, unpin and repin to avoid
the splat.

Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
[ Rewrote changelog. ]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Juri Lelli <juri.lelli@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luca Abeni <luca.abeni@unitn.it>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1470274940-17976-1-git-send-email-wanpeng.li@hotmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-10 14:02:55 +02:00
Giovanni Gherdovich
6075620b05 sched/cputime: Mitigate performance regression in times()/clock_gettime()
Commit:

  6e998916df ("sched/cputime: Fix clock_nanosleep()/clock_gettime() inconsistency")

fixed a problem whereby clock_nanosleep() followed by clock_gettime() could
allow a task to wake early. It addressed the problem by calling the scheduling
classes update_curr() when the cputimer starts.

Said change induced a considerable performance regression on the syscalls
times() and clock_gettimes(CLOCK_PROCESS_CPUTIME_ID). There are some
debuggers and applications that monitor their own performance that
accidentally depend on the performance of these specific calls.

This patch mitigates the performace loss by prefetching data in the CPU
cache, as stalls due to cache misses appear to be where most time is spent
in our benchmarks.

Here are the performance gain of this patch over v4.7-rc7 on a Sandy Bridge
box with 32 logical cores and 2 NUMA nodes. The test is repeated with a
variable number of threads, from 2 to 4*num_cpus; the results are in
seconds and correspond to the average of 10 runs; the percentage gain is
computed with (before-after)/before so a positive value is an improvement
(it's faster). The improvement varies between a few percents for 5-20
threads and more than 10% for 2 or >20 threads.

pound_clock_gettime:

    threads       4.7-rc7     patched 4.7-rc7
    [num]         [secs]      [secs (percent)]
      2           3.48        3.06 ( 11.83%)
      5           3.33        3.25 (  2.40%)
      8           3.37        3.26 (  3.30%)
     12           3.32        3.37 ( -1.60%)
     21           4.01        3.90 (  2.74%)
     30           3.63        3.36 (  7.41%)
     48           3.71        3.11 ( 16.27%)
     79           3.75        3.16 ( 15.74%)
    110           3.81        3.25 ( 14.80%)
    128           3.88        3.31 ( 14.76%)

pound_times:

    threads       4.7-rc7     patched 4.7-rc7
    [num]         [secs]      [secs (percent)]
      2           3.65        3.25 ( 11.03%)
      5           3.45        3.17 (  7.92%)
      8           3.52        3.22 (  8.69%)
     12           3.29        3.36 ( -2.04%)
     21           4.07        3.92 (  3.78%)
     30           3.87        3.40 ( 12.17%)
     48           3.79        3.16 ( 16.61%)
     79           3.88        3.28 ( 15.42%)
    110           3.90        3.38 ( 13.35%)
    128           4.00        3.38 ( 15.45%)

pound_clock_gettime and pound_clock_gettime are two benchmarks included in
the MMTests framework. They launch a given number of threads which
repeatedly call times() or clock_gettimes(). The results above can be
reproduced with cloning MMTests from github.com and running the "poundtime"
workload:

  $ git clone https://github.com/gormanm/mmtests.git
  $ cd mmtests
  $ cp configs/config-global-dhp__workload_poundtime config
  $ ./run-mmtests.sh --run-monitor $(uname -r)

The above will run "poundtime" measuring the kernel currently running on
the machine; Once a new kernel is installed and the machine rebooted,
running again

  $ cd mmtests
  $ ./run-mmtests.sh --run-monitor $(uname -r)

will produce results to compare with. A comparison table will be output
with:

  $ cd mmtests/work/log
  $ ../../compare-kernels.sh

the table will contain a lot of entries; grepping for "Amean" (as in
"arithmetic mean") will give the tables presented above. The source code
for the two benchmarks is reported at the end of this changelog for
clairity.

The cache misses addressed by this patch were found using a combination of
`perf top`, `perf record` and `perf annotate`. The incriminated lines were
found to be

    struct sched_entity *curr = cfs_rq->curr;

and

    delta_exec = now - curr->exec_start;

in the function update_curr() from kernel/sched/fair.c. This patch
prefetches the data from memory just before update_curr is called in the
interested execution path.

A comparison of the total number of cycles before and after the patch
follows; the data is obtained using `perf stat -r 10 -ddd <program>`
running over the same sequence of number of threads used above (a positive
gain is an improvement):

  threads   cycles before                 cycles after                gain

    2      19,699,563,964  +-1.19%      17,358,917,517  +-1.85%      11.88%
    5      47,401,089,566  +-2.96%      45,103,730,829  +-0.97%       4.85%
    8      80,923,501,004  +-3.01%      71,419,385,977  +-0.77%      11.74%
   12     112,326,485,473  +-0.47%     110,371,524,403  +-0.47%       1.74%
   21     193,455,574,299  +-0.72%     180,120,667,904  +-0.36%       6.89%
   30     315,073,519,013  +-1.64%     271,222,225,950  +-1.29%      13.92%
   48     321,969,515,332  +-1.48%     273,353,977,321  +-1.16%      15.10%
   79     337,866,003,422  +-0.97%     289,462,481,538  +-1.05%      14.33%
  110     338,712,691,920  +-0.78%     290,574,233,170  +-0.77%      14.21%
  128     348,384,794,006  +-0.50%     292,691,648,206  +-0.66%      15.99%

A comparison of cache miss vs total cache loads ratios, before and after
the patch (again from the `perf stat -r 10 -ddd <program>` tables):

  threads   L1 misses/total*100     L1 misses/total*100            gain
		         before                   after
      2           7.43  +-4.90%           7.36  +-4.70%           0.94%
      5          13.09  +-4.74%          13.52  +-3.73%          -3.28%
      8          13.79  +-5.61%          12.90  +-3.27%           6.45%
     12          11.57  +-2.44%           8.71  +-1.40%          24.72%
     21          12.39  +-3.92%           9.97  +-1.84%          19.53%
     30          13.91  +-2.53%          11.73  +-2.28%          15.67%
     48          13.71  +-1.59%          12.32  +-1.97%          10.14%
     79          14.44  +-0.66%          13.40  +-1.06%           7.20%
    110          15.86  +-0.50%          14.46  +-0.59%           8.83%
    128          16.51  +-0.32%          15.06  +-0.78%           8.78%

As a final note, the following shows the evolution of performance figures
in the "poundtime" benchmark and pinpoints commit 6e998916df
("sched/cputime: Fix clock_nanosleep()/clock_gettime() inconsistency") as a
major source of degradation, mostly unaddressed to this day (figures
expressed in seconds).

pound_clock_gettime:

  threads   parent of         6e998916df        4.7-rc7
	    6e998916df            itself
    2        2.23          3.68 ( -64.56%)        3.48 (-55.48%)
    5        2.83          3.78 ( -33.42%)        3.33 (-17.43%)
    8        2.84          4.31 ( -52.12%)        3.37 (-18.76%)
    12       3.09          3.61 ( -16.74%)        3.32 ( -7.17%)
    21       3.14          4.63 ( -47.36%)        4.01 (-27.71%)
    30       3.28          5.75 ( -75.37%)        3.63 (-10.80%)
    48       3.02          6.05 (-100.56%)        3.71 (-22.99%)
    79       2.88          6.30 (-118.90%)        3.75 (-30.26%)
    110      2.95          6.46 (-119.00%)        3.81 (-29.24%)
    128      3.05          6.42 (-110.08%)        3.88 (-27.04%)

pound_times:

  threads   parent of         6e998916df        4.7-rc7
	    6e998916df            itself
    2        2.27          3.73 ( -64.71%)        3.65 (-61.14%)
    5        2.78          3.77 ( -35.56%)        3.45 (-23.98%)
    8        2.79          4.41 ( -57.71%)        3.52 (-26.05%)
    12       3.02          3.56 ( -17.94%)        3.29 ( -9.08%)
    21       3.10          4.61 ( -48.74%)        4.07 (-31.34%)
    30       3.33          5.75 ( -72.53%)        3.87 (-16.01%)
    48       2.96          6.06 (-105.04%)        3.79 (-28.10%)
    79       2.88          6.24 (-116.83%)        3.88 (-34.81%)
    110      2.98          6.37 (-114.08%)        3.90 (-31.12%)
    128      3.10          6.35 (-104.61%)        4.00 (-28.87%)

The source code of the two benchmarks follows. To compile the two:

  NR_THREADS=42
  for FILE in pound_times pound_clock_gettime; do
      gcc -lrt -O2 -lpthread -DNUM_THREADS=$NR_THREADS $FILE.c -o $FILE
  done

==== BEGIN pound_times.c ====

struct tms start;

void *pound (void *threadid)
{
  struct tms end;
  int oldutime = 0;
  int utime;
  int i;
  for (i = 0; i < 5000000 / NUM_THREADS; i++) {
          times(&end);
          utime = ((int)end.tms_utime - (int)start.tms_utime);
          if (oldutime > utime) {
            printf("utime decreased, was %d, now %d!\n", oldutime, utime);
          }
          oldutime = utime;
  }
  pthread_exit(NULL);
}

int main()
{
  pthread_t th[NUM_THREADS];
  long i;
  times(&start);
  for (i = 0; i < NUM_THREADS; i++) {
    pthread_create (&th[i], NULL, pound, (void *)i);
  }
  pthread_exit(NULL);
  return 0;
}
==== END pound_times.c ====

==== BEGIN pound_clock_gettime.c ====

void *pound (void *threadid)
{
	struct timespec ts;
	int rc, i;
	unsigned long prev = 0, this = 0;

	for (i = 0; i < 5000000 / NUM_THREADS; i++) {
		rc = clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &ts);
		if (rc < 0)
			perror("clock_gettime");
		this = (ts.tv_sec * 1000000000) + ts.tv_nsec;
		if (0 && this < prev)
			printf("%lu ns timewarp at iteration %d\n", prev - this, i);
		prev = this;
	}
	pthread_exit(NULL);
}

int main()
{
	pthread_t th[NUM_THREADS];
	long rc, i;
	pid_t pgid;

	for (i = 0; i < NUM_THREADS; i++) {
		rc = pthread_create(&th[i], NULL, pound, (void *)i);
		if (rc < 0)
			perror("pthread_create");
	}

	pthread_exit(NULL);
	return 0;
}
==== END pound_clock_gettime.c ====

Suggested-by: Mike Galbraith <mgalbraith@suse.de>
Signed-off-by: Giovanni Gherdovich <ggherdovich@suse.cz>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stanislaw Gruszka <sgruszka@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1470385316-15027-2-git-send-email-ggherdovich@suse.cz
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-10 13:32:56 +02:00
Xunlei Pang
b8922125e4 sched/fair: Fix typo in sync_throttle()
We should update cfs_rq->throttled_clock_task, not
pcfs_rq->throttle_clock_task.

The effects of this bug was probably occasionally erratic
group scheduling, particularly in cgroups-intense workloads.

Signed-off-by: Xunlei Pang <xlpang@redhat.com>
[ Added changelog. ]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 55e16d30bd ("sched/fair: Rework throttle_count sync")
Link: http://lkml.kernel.org/r/1468050862-18864-1-git-send-email-xlpang@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-10 13:32:55 +02:00
Tommaso Cucinotta
a23eadfae2 sched/deadline: Fix wrap-around in DL heap
Current code in cpudeadline.c has a bug in re-heapifying when adding a
new element at the end of the heap, because a deadline value of 0 is
temporarily set in the new elem, then cpudl_change_key() is called
with the actual elem deadline as param.

However, the function compares the new deadline to set with the one
previously in the elem, which is 0.  So, if current absolute deadlines
grew so much to have negative values as s64, the comparison in
cpudl_change_key() makes the wrong decision.  Instead, as from
dl_time_before(), the kernel should handle correctly abs deadlines
wrap-arounds.

This patch fixes the problem with a minimally invasive change that
forces cpudl_change_key() to heapify up in this case.

Signed-off-by: Tommaso Cucinotta <tommaso.cucinotta@sssup.it>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Luca Abeni <luca.abeni@unitn.it>
Cc: Juri Lelli <juri.lelli@arm.com>
Cc: Juri Lelli <juri.lelli@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1468921493-10054-2-git-send-email-tommaso.cucinotta@sssup.it
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-10 13:32:55 +02:00
Peter Zijlstra
e48c178814 perf/core: Optimize perf_pmu_sched_task()
For perf record -b, which requires the pmu::sched_task callback the
current code is rather expensive:

     7.68%  sched-pipe  [kernel.vmlinux]    [k] perf_pmu_sched_task
     5.95%  sched-pipe  [kernel.vmlinux]    [k] __switch_to
     5.20%  sched-pipe  [kernel.vmlinux]    [k] __intel_pmu_disable_all
     3.95%  sched-pipe  perf                [.] worker_thread

The problem is that it will iterate all registered PMUs, most of which
will not have anything to do. Avoid this by keeping an explicit list
of PMUs that have requested the callback.

The perf_sched_cb_{inc,dec}() functions already takes the required pmu
argument, and now that these functions are no longer called from NMI
context we can use them to manage a list.

With this patch applied the function doesn't show up in the top 4
anymore (it dropped to 18th place).

     6.67%  sched-pipe  [kernel.vmlinux]    [k] __switch_to
     6.18%  sched-pipe  [kernel.vmlinux]    [k] __intel_pmu_disable_all
     3.92%  sched-pipe  [kernel.vmlinux]    [k] switch_mm_irqs_off
     3.71%  sched-pipe  perf                [.] worker_thread

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-10 13:13:28 +02:00
Peter Zijlstra
09e61b4f78 perf/x86/intel: Rework the large PEBS setup code
In order to allow optimizing perf_pmu_sched_task() we must ensure
perf_sched_cb_{inc,dec}() are no longer called from NMI context; this
means that pmu::{start,stop}() can no longer use them.

Prepare for this by reworking the whole large PEBS setup code.

The current code relied on the cpuc->pebs_enabled state, however since
that reflects the current active state as per pmu::{start,stop}() we
can no longer rely on this.

Introduce two counters: cpuc->n_pebs and cpuc->n_large_pebs which
count the total number of PEBS events and the number of PEBS events
that have FREERUNNING set, resp.. With this we can tell if the current
setup requires a single record interrupt threshold or can use a larger
buffer.

This also improves the code in that it re-enables the large threshold
once the PEBS event that required single record gets removed.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-10 13:13:24 +02:00
Mark Rutland
3f005e7de3 perf/core: Sched out groups atomically
Groups of events are supposed to be scheduled atomically, such that it
is possible to derive meaningful ratios between their values.

We take great pains to achieve this when scheduling event groups to a
PMU in group_sched_in(), calling {start,commit}_txn() (which fall back
to perf_pmu_{disable,enable}() if necessary) to provide this guarantee.
However we don't mirror this in group_sched_out(), and in some cases
events will not be scheduled out atomically.

For example, if we disable an event group with PERF_EVENT_IOC_DISABLE,
we'll cross-call __perf_event_disable() for the group leader, and will
call group_sched_out() without having first disabled the relevant PMU.
We will disable/enable the PMU around each pmu->del() call, but between
each call the PMU will be enabled and events may count.

Avoid this by explicitly disabling and enabling the PMU around event
removal in group_sched_out(), mirroring what we do in group_sched_in().

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: http://lkml.kernel.org/r/1469553141-28314-1-git-send-email-mark.rutland@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-10 13:13:23 +02:00
David Carrillo-Cisneros
db4a835601 perf/core: Set cgroup in CPU contexts for new cgroup events
There's a perf stat bug easy to observer on a machine with only one cgroup:

  $ perf stat -e cycles -I 1000 -C 0 -G /
  #          time             counts unit events
      1.000161699      <not counted>      cycles                    /
      2.000355591      <not counted>      cycles                    /
      3.000565154      <not counted>      cycles                    /
      4.000951350      <not counted>      cycles                    /

We'd expect some output there.

The underlying problem is that there is an optimization in
perf_cgroup_sched_{in,out}() that skips the switch of cgroup events
if the old and new cgroups in a task switch are the same.

This optimization interacts with the current code in two ways
that cause a CPU context's cgroup (cpuctx->cgrp) to be NULL even if a
cgroup event matches the current task. These are:

  1. On creation of the first cgroup event in a CPU: In current code,
  cpuctx->cpu is only set in perf_cgroup_sched_in, but due to the
  aforesaid optimization, perf_cgroup_sched_in will run until the next
  cgroup switches in that CPU. This may happen late or never happen,
  depending on system's number of cgroups, CPU load, etc.

  2. On deletion of the last cgroup event in a cpuctx: In list_del_event,
  cpuctx->cgrp is set NULL. Any new cgroup event will not be sched in
  because cpuctx->cgrp == NULL until a cgroup switch occurs and
  perf_cgroup_sched_in is executed (updating cpuctx->cgrp).

This patch fixes both problems by setting cpuctx->cgrp in list_add_event,
mirroring what list_del_event does when removing a cgroup event from CPU
context, as introduced in:

  commit 68cacd2916 ("perf_events: Fix stale ->cgrp pointer in update_cgrp_time_from_cpuctx()")

With this patch, cpuctx->cgrp is always set/clear when installing/removing
the first/last cgroup event in/from the CPU context. With cpuctx->cgrp
correctly set, event_filter_match works as intended when events are
sched in/out.

After the fix, the output is as expected:

  $ perf stat -e cycles -I 1000 -a -G /
  #         time             counts unit events
     1.004699159          627342882      cycles                    /
     2.007397156          615272690      cycles                    /
     3.010019057          616726074      cycles                    /

Signed-off-by: David Carrillo-Cisneros <davidcc@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul Turner <pjt@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vegard Nossum <vegard.nossum@gmail.com>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: http://lkml.kernel.org/r/1470124092-113192-1-git-send-email-davidcc@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-10 13:05:52 +02:00
Peter Zijlstra
0b8f1e2e26 perf/core: Fix sideband list-iteration vs. event ordering NULL pointer deference crash
Vegard Nossum reported that perf fuzzing generates a NULL
pointer dereference crash:

> Digging a bit deeper into this, it seems the event itself is getting
> created by perf_event_open() and it gets added to the pmu_event_list
> through:
>
> perf_event_open()
>  - perf_event_alloc()
>     - account_event()
>        - account_pmu_sb_event()
>           - attach_sb_event()
>
> so at this point the event is being attached but its ->ctx is still
> NULL. It seems like ->ctx is set just a bit later in
> perf_event_open(), though.
>
> But before that, __schedule() comes along and creates a stack trace
> similar to the one above:
>
> __schedule()
>  - __perf_event_task_sched_out()
>    - perf_iterate_sb()
>      - perf_iterate_sb_cpu()
>         - event_filter_match()
>           - perf_cgroup_match()
>             - __get_cpu_context()
>               - (dereference ctx which is NULL)
>
> So I guess the question is... should the event be attached (= put on
> the list) before ->ctx gets set? Or should the cgroup code check for a
> NULL ->ctx?

The latter seems like the simplest solution. Moving the list-add later
creates a bit of a mess.

Reported-by: Vegard Nossum <vegard.nossum@gmail.com>
Tested-by: Vegard Nossum <vegard.nossum@gmail.com>
Tested-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Carrillo-Cisneros <davidcc@google.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: f2fb6bef92 ("perf/core: Optimize side-band event delivery")
Link: http://lkml.kernel.org/r/20160804123724.GN6862@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-10 13:05:51 +02:00
Zefan Li
06f4e94898 cpuset: make sure new tasks conform to the current config of the cpuset
A new task inherits cpus_allowed and mems_allowed masks from its parent,
but if someone changes cpuset's config by writing to cpuset.cpus/cpuset.mems
before this new task is inserted into the cgroup's task list, the new task
won't be updated accordingly.

Signed-off-by: Zefan Li <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: stable@vger.kernel.org
2016-08-09 23:58:01 -04:00
Linus Torvalds
a0cba2179e Revert "printk: create pr_<level> functions"
This reverts commit 874f9c7da9.

Geert Uytterhoeven reports:
 "This change seems to have an (unintendent?) side-effect.

  Before, pr_*() calls without a trailing newline characters would be
  printed with a newline character appended, both on the console and in
  the output of the dmesg command.

  After this commit, no new line character is appended, and the output
  of the next pr_*() call of the same type may be appended, like in:

    - Truncating RAM at 0x0000000040000000-0x00000000c0000000 to -0x0000000070000000
    - Ignoring RAM at 0x0000000200000000-0x0000000240000000 (!CONFIG_HIGHMEM)
    + Truncating RAM at 0x0000000040000000-0x00000000c0000000 to -0x0000000070000000Ignoring RAM at 0x0000000200000000-0x0000000240000000 (!CONFIG_HIGHMEM)"

Joe Perches says:
 "No, that is not intentional.

  The newline handling code inside vprintk_emit is a bit involved and
  for now I suggest a revert until this has all the same behavior as
  earlier"

Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Requested-by: Joe Perches <joe@perches.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-08-09 10:48:18 -07:00
Chris Metcalf
46c8f0b077 timers: Fix get_next_timer_interrupt() computation
The tick_nohz_stop_sched_tick() routine is not properly
canceling the sched timer when nothing is pending, because
get_next_timer_interrupt() is no longer returning KTIME_MAX in
that case.  This causes periodic interrupts when none are needed.

When determining the next interrupt time, we first use
__next_timer_interrupt() to get the first expiring timer in the
timer wheel.  If no timer is found, we return the base clock value
plus NEXT_TIMER_MAX_DELTA to indicate there is no timer in the
timer wheel.

Back in get_next_timer_interrupt(), we set the "expires" value
by converting the timer wheel expiry (in ticks) to a nsec value.
But we don't want to do this if the timer wheel expiry value
indicates no timer; we want to return KTIME_MAX.

Prior to commit 500462a9de ("timers: Switch to a non-cascading
wheel") we checked base->active_timers to see if any timers
were active, and if not, we didn't touch the expiry value and so
properly returned KTIME_MAX.  Now we don't have active_timers.

To fix this, we now just check the timer wheel expiry value to
see if it is "now + NEXT_TIMER_MAX_DELTA", and if it is, we don't
try to compute a new value based on it, but instead simply let the
KTIME_MAX value in expires remain.

Fixes: 500462a9de "timers: Switch to a non-cascading wheel"
Signed-off-by: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: John Stultz <john.stultz@linaro.org>
Link: http://lkml.kernel.org/r/1470688147-22287-1-git-send-email-cmetcalf@mellanox.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-08-09 09:31:55 +02:00
Marc Zyngier
f3b0946d62 genirq/msi: Make sure PCI MSIs are activated early
Bharat Kumar Gogada reported issues with the generic MSI code, where the
end-point ended up with garbage in its MSI configuration (both for the vector
and the message).

It turns out that the two MSI paths in the kernel are doing slightly different
things:

generic MSI: disable MSI -> allocate MSI -> enable MSI -> setup EP
PCI MSI: disable MSI -> allocate MSI -> setup EP -> enable MSI

And it turns out that end-points are allowed to latch the content of the MSI
configuration registers as soon as MSIs are enabled.  In Bharat's case, the
end-point ends up using whatever was there already, which is not what you
want.

In order to make things converge, we introduce a new MSI domain flag
(MSI_FLAG_ACTIVATE_EARLY) that is unconditionally set for PCI/MSI. When set,
this flag forces the programming of the end-point as soon as the MSIs are
allocated.

A consequence of this is that we have an extra activate in irq_startup, but
that should be without much consequence.

tglx: 

 - Several people reported a VMWare regression with PCI/MSI-X passthrough. It
   turns out that the patch also cures that issue.

 - We need to have a look at the MSI disable interrupt path, where we write
   the msg to all zeros without disabling MSI in the PCI device. Is that
   correct?

Fixes: 52f518a3a7 "x86/MSI: Use hierarchical irqdomains to manage MSI interrupts"
Reported-and-tested-by: Bharat Kumar Gogada <bharat.kumar.gogada@xilinx.com>
Reported-and-tested-by: Foster Snowhill <forst@forstwoof.ru>
Reported-by: Matthias Prager <linux@matthiasprager.de>
Reported-by: Jason Taylor <jason.taylor@simplivity.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: linux-pci@vger.kernel.org
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1468426713-31431-1-git-send-email-marc.zyngier@arm.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-08-09 09:19:32 +02:00
Eric W. Biederman
703286608a netns: Add a limit on the number of net namespaces
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2016-08-08 14:42:04 -05:00
Eric W. Biederman
d08311dd6f cgroupns: Add a limit on the number of cgroup namespaces
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2016-08-08 14:42:03 -05:00
Eric W. Biederman
aba3566163 ipcns: Add a limit on the number of ipc namespaces
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2016-08-08 14:42:03 -05:00
Eric W. Biederman
f7af3d1c03 utsns: Add a limit on the number of uts namespaces
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2016-08-08 14:42:02 -05:00
Eric W. Biederman
f333c700c6 pidns: Add a limit on the number of pid namespaces
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2016-08-08 14:42:01 -05:00
Eric W. Biederman
25f9c0817c userns: Generalize the user namespace count into ucount
The same kind of recursive sane default limit and policy
countrol that has been implemented for the user namespace
is desirable for the other namespaces, so generalize
the user namespace refernce count into a ucount.

Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2016-08-08 14:41:52 -05:00
Eric W. Biederman
f6b2db1a3e userns: Make the count of user namespaces per user
Add a structure that is per user and per user ns and use it to hold
the count of user namespaces.  This makes prevents one user from
creating denying service to another user by creating the maximum
number of user namespaces.

Rename the sysctl export of the maximum count from
/proc/sys/userns/max_user_namespaces to /proc/sys/user/max_user_namespaces
to reflect that the count is now per user.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2016-08-08 14:40:30 -05:00
Eric W. Biederman
b376c3e1b6 userns: Add a limit on the number of user namespaces
Export the export the maximum number of user namespaces as
/proc/sys/userns/max_user_namespaces.

Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2016-08-08 13:41:24 -05:00
Andreas Ziegler
574673c231 printk: Remove unnecessary #ifdef CONFIG_PRINTK
In commit 874f9c7da9 ("printk: create pr_<level> functions"), new
pr_level defines were added to printk.c.

These new defines are guarded by an #ifdef CONFIG_PRINTK - however,
there is already a surrounding #ifdef CONFIG_PRINTK starting a lot
earlier in line 249 which means the newly introduced #ifdef is
unnecessary.

Let's remove it to avoid confusion.

Signed-off-by: Andreas Ziegler <andreas.ziegler@fau.de>
Cc: Joe Perches <joe@perches.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-08-08 11:29:39 -07:00
Eric W. Biederman
dbec28460a userns: Add per user namespace sysctls.
Limit per userns sysctls to only be opened for write by a holder
of CAP_SYS_RESOURCE.

Add all of the necessary boilerplate for having per user namespace
sysctls.

Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2016-08-08 13:18:58 -05:00
Eric W. Biederman
b032132c3c userns: Free user namespaces in process context
Add the necessary boiler plate to move freeing of user namespaces into
work queue and thus into process context where things can sleep.

This is a necessary precursor to per user namespace sysctls.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2016-08-08 09:17:18 -05:00
Jens Axboe
1eff9d322a block: rename bio bi_rw to bi_opf
Since commit 63a4cc2486, bio->bi_rw contains flags in the lower
portion and the op code in the higher portions. This means that
old code that relies on manually setting bi_rw is most likely
going to be broken. Instead of letting that brokeness linger,
rename the member, to force old and out-of-tree code to break
at compile time instead of at runtime.

No intended functional changes in this commit.

Signed-off-by: Jens Axboe <axboe@fb.com>
2016-08-07 14:41:02 -06:00
Alexei Starovoitov
a6ed3ea65d bpf: restore behavior of bpf_map_update_elem
The introduction of pre-allocated hash elements inadvertently broke
the behavior of bpf hash maps where users expected to call
bpf_map_update_elem() without considering that the map can be full.
Some programs do:
old_value = bpf_map_lookup_elem(map, key);
if (old_value) {
  ... prepare new_value on stack ...
  bpf_map_update_elem(map, key, new_value);
}
Before pre-alloc the update() for existing element would work even
in 'map full' condition. Restore this behavior.

The above program could have updated old_value in place instead of
update() which would be faster and most programs use that approach,
but sometimes the values are large and the programs use update()
helper to do atomic replacement of the element.
Note we cannot simply update element's value in-place like percpu
hash map does and have to allocate extra num_possible_cpu elements
and use this extra reserve when the map is full.

Fixes: 6c90598174 ("bpf: pre-allocate hash map elements")
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-08-06 20:49:19 -04:00
Linus Torvalds
db8262787e Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf updates from Ingo Molnar:
 "Mostly tooling fixes and some late tooling updates, plus two perf
  related printk message fixes"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf tests bpf: Use SyS_epoll_wait alias
  perf tests: objdump output can contain multi byte chunks
  perf record: Add --sample-cpu option
  perf hists: Introduce output_resort_cb method
  perf tools: Move config/Makefile into Makefile.config
  perf tests: Add test for bitmap_scnprintf function
  tools lib: Add bitmap_and function
  tools lib: Add bitmap_scnprintf function
  tools lib: Add bitmap_alloc function
  tools lib traceevent: Ignore generated library files
  perf tools: Fix build failure on perl script context
  perf/core: Change log level for duration warning to KERN_INFO
  perf annotate: Plug filename string leak
  perf annotate: Introduce strerror for handling symbol__disassemble() errors
  perf annotate: Rename symbol__annotate() to symbol__disassemble()
  perf/x86: Modify error message in virtualized environment
  perf target: str_error_r() always returns the buffer it receives
  perf annotate: Use pipe + fork instead of popen
  perf evsel: Introduce constructor for cycles event
2016-08-06 09:10:36 -04:00
Linus Torvalds
2cfd716d27 powerpc updates for 4.8 #2
Fixes:
  - Fix early access to cpu_spec relocation from Benjamin Herrenschmidt
  - Fix incorrect event codes in power9-event-list from Madhavan Srinivasan
  - Move register_process_table() out of ppc_md from Michael Ellerman
 
 Use jump_label for [cpu|mmu]_has_feature() from Aneesh Kumar K.V, Kevin Hao and Michael Ellerman:
  - Add mmu_early_init_devtree() from Michael Ellerman
  - Move disable_radix handling into mmu_early_init_devtree() from Michael Ellerman
  - Do hash device tree scanning earlier from Michael Ellerman
  - Do radix device tree scanning earlier from Michael Ellerman
  - Do feature patching before MMU init from Michael Ellerman
  - Check features don't change after patching from Michael Ellerman
  - Make MMU_FTR_RADIX a MMU family feature from Aneesh Kumar K.V
  - Convert mmu_has_feature() to returning bool from Michael Ellerman
  - Convert cpu_has_feature() to returning bool from Michael Ellerman
  - Define radix_enabled() in one place & use static inline from Michael Ellerman
  - Add early_[cpu|mmu]_has_feature() from Michael Ellerman
  - Convert early cpu/mmu feature check to use the new helpers from Aneesh Kumar K.V
  - jump_label: Make it possible for arches to invoke jump_label_init() earlier from Kevin Hao
  - Call jump_label_init() in apply_feature_fixups() from Aneesh Kumar K.V
  - Remove mfvtb() from Kevin Hao
  - Move cpu_has_feature() to a separate file from Kevin Hao
  - Add kconfig option to use jump labels for cpu/mmu_has_feature() from Michael Ellerman
  - Add option to use jump label for cpu_has_feature() from Kevin Hao
  - Add option to use jump label for mmu_has_feature() from Kevin Hao
  - Catch usage of cpu/mmu_has_feature() before jump label init from Aneesh Kumar K.V
  - Annotate jump label assembly from Michael Ellerman
 
 TLB flush enhancements from Aneesh Kumar K.V:
  - radix: Implement tlb mmu gather flush efficiently
  - Add helper for finding SLBE LLP encoding
  - Use hugetlb flush functions
  - Drop multiple definition of mm_is_core_local
  - radix: Add tlb flush of THP ptes
  - radix: Rename function and drop unused arg
  - radix/hugetlb: Add helper for finding page size
  - hugetlb: Add flush_hugetlb_tlb_range
  - remove flush_tlb_page_nohash
 
 Add new ptrace regsets from Anshuman Khandual and Simon Guo:
  - elf: Add powerpc specific core note sections
  - Add the function flush_tmregs_to_thread
  - Enable in transaction NT_PRFPREG ptrace requests
  - Enable in transaction NT_PPC_VMX ptrace requests
  - Enable in transaction NT_PPC_VSX ptrace requests
  - Adapt gpr32_get, gpr32_set functions for transaction
  - Enable support for NT_PPC_CGPR
  - Enable support for NT_PPC_CFPR
  - Enable support for NT_PPC_CVMX
  - Enable support for NT_PPC_CVSX
  - Enable support for TM SPR state
  - Enable NT_PPC_TM_CTAR, NT_PPC_TM_CPPR, NT_PPC_TM_CDSCR
  - Enable support for NT_PPPC_TAR, NT_PPC_PPR, NT_PPC_DSCR
  - Enable support for EBB registers
  - Enable support for Performance Monitor registers
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Merge tag 'powerpc-4.8-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

Pull more powerpc updates from Michael Ellerman:
 "These were delayed for various reasons, so I let them sit in next a
  bit longer, rather than including them in my first pull request.

  Fixes:
   - Fix early access to cpu_spec relocation from Benjamin Herrenschmidt
   - Fix incorrect event codes in power9-event-list from Madhavan Srinivasan
   - Move register_process_table() out of ppc_md from Michael Ellerman

  Use jump_label use for [cpu|mmu]_has_feature():
   - Add mmu_early_init_devtree() from Michael Ellerman
   - Move disable_radix handling into mmu_early_init_devtree() from Michael Ellerman
   - Do hash device tree scanning earlier from Michael Ellerman
   - Do radix device tree scanning earlier from Michael Ellerman
   - Do feature patching before MMU init from Michael Ellerman
   - Check features don't change after patching from Michael Ellerman
   - Make MMU_FTR_RADIX a MMU family feature from Aneesh Kumar K.V
   - Convert mmu_has_feature() to returning bool from Michael Ellerman
   - Convert cpu_has_feature() to returning bool from Michael Ellerman
   - Define radix_enabled() in one place & use static inline from Michael Ellerman
   - Add early_[cpu|mmu]_has_feature() from Michael Ellerman
   - Convert early cpu/mmu feature check to use the new helpers from Aneesh Kumar K.V
   - jump_label: Make it possible for arches to invoke jump_label_init() earlier from Kevin Hao
   - Call jump_label_init() in apply_feature_fixups() from Aneesh Kumar K.V
   - Remove mfvtb() from Kevin Hao
   - Move cpu_has_feature() to a separate file from Kevin Hao
   - Add kconfig option to use jump labels for cpu/mmu_has_feature() from Michael Ellerman
   - Add option to use jump label for cpu_has_feature() from Kevin Hao
   - Add option to use jump label for mmu_has_feature() from Kevin Hao
   - Catch usage of cpu/mmu_has_feature() before jump label init from Aneesh Kumar K.V
   - Annotate jump label assembly from Michael Ellerman

  TLB flush enhancements from Aneesh Kumar K.V:
   - radix: Implement tlb mmu gather flush efficiently
   - Add helper for finding SLBE LLP encoding
   - Use hugetlb flush functions
   - Drop multiple definition of mm_is_core_local
   - radix: Add tlb flush of THP ptes
   - radix: Rename function and drop unused arg
   - radix/hugetlb: Add helper for finding page size
   - hugetlb: Add flush_hugetlb_tlb_range
   - remove flush_tlb_page_nohash

  Add new ptrace regsets from Anshuman Khandual and Simon Guo:
   - elf: Add powerpc specific core note sections
   - Add the function flush_tmregs_to_thread
   - Enable in transaction NT_PRFPREG ptrace requests
   - Enable in transaction NT_PPC_VMX ptrace requests
   - Enable in transaction NT_PPC_VSX ptrace requests
   - Adapt gpr32_get, gpr32_set functions for transaction
   - Enable support for NT_PPC_CGPR
   - Enable support for NT_PPC_CFPR
   - Enable support for NT_PPC_CVMX
   - Enable support for NT_PPC_CVSX
   - Enable support for TM SPR state
   - Enable NT_PPC_TM_CTAR, NT_PPC_TM_CPPR, NT_PPC_TM_CDSCR
   - Enable support for NT_PPPC_TAR, NT_PPC_PPR, NT_PPC_DSCR
   - Enable support for EBB registers
   - Enable support for Performance Monitor registers"

* tag 'powerpc-4.8-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (48 commits)
  powerpc/mm: Move register_process_table() out of ppc_md
  powerpc/perf: Fix incorrect event codes in power9-event-list
  powerpc/32: Fix early access to cpu_spec relocation
  powerpc/ptrace: Enable support for Performance Monitor registers
  powerpc/ptrace: Enable support for EBB registers
  powerpc/ptrace: Enable support for NT_PPPC_TAR, NT_PPC_PPR, NT_PPC_DSCR
  powerpc/ptrace: Enable NT_PPC_TM_CTAR, NT_PPC_TM_CPPR, NT_PPC_TM_CDSCR
  powerpc/ptrace: Enable support for TM SPR state
  powerpc/ptrace: Enable support for NT_PPC_CVSX
  powerpc/ptrace: Enable support for NT_PPC_CVMX
  powerpc/ptrace: Enable support for NT_PPC_CFPR
  powerpc/ptrace: Enable support for NT_PPC_CGPR
  powerpc/ptrace: Adapt gpr32_get, gpr32_set functions for transaction
  powerpc/ptrace: Enable in transaction NT_PPC_VSX ptrace requests
  powerpc/ptrace: Enable in transaction NT_PPC_VMX ptrace requests
  powerpc/ptrace: Enable in transaction NT_PRFPREG ptrace requests
  powerpc/process: Add the function flush_tmregs_to_thread
  elf: Add powerpc specific core note sections
  powerpc/mm: remove flush_tlb_page_nohash
  powerpc/mm/hugetlb: Add flush_hugetlb_tlb_range
  ...
2016-08-05 09:00:54 -04:00
Linus Torvalds
fb1b83d3ff Removed the MODULE_SIG_FORCE-means-no-MODULE_FORCE_LOAD patch.
Only interesting thing here is Jessica's patch to add ro_after_init support
 to modules.  The rest are all trivia.
 
 Cheers,
 Rusty.
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Merge tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux

Pull module updates from Rusty Russell:
 "The only interesting thing here is Jessica's patch to add
  ro_after_init support to modules.  The rest are all trivia"

* tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux:
  extable.h: add stddef.h so "NULL" definition is not implicit
  modules: add ro_after_init support
  jump_label: disable preemption around __module_text_address().
  exceptions: fork exception table content from module.h into extable.h
  modules: Add kernel parameter to blacklist modules
  module: Do a WARN_ON_ONCE() for assert module mutex not held
  Documentation/module-signing.txt: Note need for version info if reusing a key
  module: Invalidate signatures on force-loaded modules
  module: Issue warnings when tainting kernel
  module: fix redundant test.
  module: fix noreturn attribute for __module_put_and_exit()
2016-08-04 09:14:38 -04:00
Jason Baron
1f69bf9c61 jump_label: remove bug.h, atomic.h dependencies for HAVE_JUMP_LABEL
The current jump_label.h includes bug.h for things such as WARN_ON().
This makes the header problematic for inclusion by kernel.h or any
headers that kernel.h includes, since bug.h includes kernel.h (circular
dependency).  The inclusion of atomic.h is similarly problematic.  Thus,
this should make jump_label.h 'includable' from most places.

Link: http://lkml.kernel.org/r/7060ce35ddd0d20b33bf170685e6b0fab816bdf2.1467837322.git.jbaron@akamai.com
Signed-off-by: Jason Baron <jbaron@akamai.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Joe Perches <joe@perches.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-08-04 08:50:07 -04:00
Masahiro Yamada
97f2645f35 tree-wide: replace config_enabled() with IS_ENABLED()
The use of config_enabled() against config options is ambiguous.  In
practical terms, config_enabled() is equivalent to IS_BUILTIN(), but the
author might have used it for the meaning of IS_ENABLED().  Using
IS_ENABLED(), IS_BUILTIN(), IS_MODULE() etc.  makes the intention
clearer.

This commit replaces config_enabled() with IS_ENABLED() where possible.
This commit is only touching bool config options.

I noticed two cases where config_enabled() is used against a tristate
option:

 - config_enabled(CONFIG_HWMON)
  [ drivers/net/wireless/ath/ath10k/thermal.c ]

 - config_enabled(CONFIG_BACKLIGHT_CLASS_DEVICE)
  [ drivers/gpu/drm/gma500/opregion.c ]

I did not touch them because they should be converted to IS_BUILTIN()
in order to keep the logic, but I was not sure it was the authors'
intention.

Link: http://lkml.kernel.org/r/1465215656-20569-1-git-send-email-yamada.masahiro@socionext.com
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Stas Sergeev <stsp@list.ru>
Cc: Matt Redfearn <matt.redfearn@imgtec.com>
Cc: Joshua Kinard <kumba@gentoo.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Cc: "Dmitry V. Levin" <ldv@altlinux.org>
Cc: yu-cheng yu <yu-cheng.yu@intel.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Will Drewry <wad@chromium.org>
Cc: Nikolay Martynov <mar.kolya@gmail.com>
Cc: Huacai Chen <chenhc@lemote.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Cc: Rafal Milecki <zajec5@gmail.com>
Cc: James Cowgill <James.Cowgill@imgtec.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Alex Smith <alex.smith@imgtec.com>
Cc: Adam Buchbinder <adam.buchbinder@gmail.com>
Cc: Qais Yousef <qais.yousef@imgtec.com>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Mikko Rapeli <mikko.rapeli@iki.fi>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Brian Norris <computersforpeace@gmail.com>
Cc: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com>
Cc: "Luis R. Rodriguez" <mcgrof@do-not-panic.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Roland McGrath <roland@hack.frob.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Kalle Valo <kvalo@qca.qualcomm.com>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Tony Wu <tung7970@gmail.com>
Cc: Huaitong Han <huaitong.han@intel.com>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Juergen Gross <jgross@suse.com>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Andrea Gelmini <andrea.gelmini@gelma.net>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Rabin Vincent <rabin@rab.in>
Cc: "Maciej W. Rozycki" <macro@imgtec.com>
Cc: David Daney <david.daney@cavium.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-08-04 08:50:07 -04:00
Jessica Yu
444d13ff10 modules: add ro_after_init support
Add ro_after_init support for modules by adding a new page-aligned section
in the module layout (after rodata) for ro_after_init data and enabling RO
protection for that section after module init runs.

Signed-off-by: Jessica Yu <jeyu@redhat.com>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2016-08-04 10:16:55 +09:30
Rusty Russell
bdc9f37355 jump_label: disable preemption around __module_text_address().
Steven reported a warning caused by not holding module_mutex or
rcu_read_lock_sched: his backtrace was corrupted but a quick audit
found this possible cause.  It's wrong anyway...

Reported-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2016-08-04 10:16:54 +09:30
Prarit Bhargava
be7de5f91f modules: Add kernel parameter to blacklist modules
Blacklisting a module in linux has long been a problem.  The current
procedure is to use rd.blacklist=module_name, however, that doesn't
cover the case after the initramfs and before a boot prompt (where one
is supposed to use /etc/modprobe.d/blacklist.conf to blacklist
runtime loading). Using rd.shell to get an early prompt is hit-or-miss,
and doesn't cover all situations AFAICT.

This patch adds this functionality of permanently blacklisting a module
by its name via the kernel parameter module_blacklist=module_name.

[v2]: Rusty, use core_param() instead of __setup() which simplifies
things.

[v3]: Rusty, undo wreckage from strsep()

[v4]: Rusty, simpler version of blacklisted()

Signed-off-by: Prarit Bhargava <prarit@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: linux-doc@vger.kernel.org
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2016-08-04 10:16:53 +09:30
Steven Rostedt
9502514f28 module: Do a WARN_ON_ONCE() for assert module mutex not held
When running with lockdep enabled, I triggered the WARN_ON() in the
module code that asserts when module_mutex or rcu_read_lock_sched are
not held. The issue I have is that this can also be called from the
dump_stack() code, causing us to enter an infinite loop...

 ------------[ cut here ]------------
 WARNING: CPU: 1 PID: 0 at kernel/module.c:268 module_assert_mutex_or_preempt+0x3c/0x3e
 Modules linked in: ip6t_REJECT nf_reject_ipv6 nf_conntrack_ipv6
 CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.7.0-rc3-test-00013-g501c2375253c #14
 Hardware name: MSI MS-7823/CSM-H87M-G43 (MS-7823), BIOS V1.6 02/22/2014
  ffff880215e8fa70 ffff880215e8fa70 ffffffff812fc8e3 0000000000000000
  ffffffff81d3e55b ffff880215e8fac0 ffffffff8104fc88 ffffffff8104fcab
  0000000915e88300 0000000000000046 ffffffffa019b29a 0000000000000001
 Call Trace:
  [<ffffffff812fc8e3>] dump_stack+0x67/0x90
  [<ffffffff8104fc88>] __warn+0xcb/0xe9
  [<ffffffff8104fcab>] ? warn_slowpath_null+0x5/0x1f
 ------------[ cut here ]------------
 WARNING: CPU: 1 PID: 0 at kernel/module.c:268 module_assert_mutex_or_preempt+0x3c/0x3e
 Modules linked in: ip6t_REJECT nf_reject_ipv6 nf_conntrack_ipv6
 CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.7.0-rc3-test-00013-g501c2375253c #14
 Hardware name: MSI MS-7823/CSM-H87M-G43 (MS-7823), BIOS V1.6 02/22/2014
  ffff880215e8f7a0 ffff880215e8f7a0 ffffffff812fc8e3 0000000000000000
  ffffffff81d3e55b ffff880215e8f7f0 ffffffff8104fc88 ffffffff8104fcab
  0000000915e88300 0000000000000046 ffffffffa019b29a 0000000000000001
 Call Trace:
  [<ffffffff812fc8e3>] dump_stack+0x67/0x90
  [<ffffffff8104fc88>] __warn+0xcb/0xe9
  [<ffffffff8104fcab>] ? warn_slowpath_null+0x5/0x1f
 ------------[ cut here ]------------
 WARNING: CPU: 1 PID: 0 at kernel/module.c:268 module_assert_mutex_or_preempt+0x3c/0x3e
 Modules linked in: ip6t_REJECT nf_reject_ipv6 nf_conntrack_ipv6
 CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.7.0-rc3-test-00013-g501c2375253c #14
 Hardware name: MSI MS-7823/CSM-H87M-G43 (MS-7823), BIOS V1.6 02/22/2014
  ffff880215e8f4d0 ffff880215e8f4d0 ffffffff812fc8e3 0000000000000000
  ffffffff81d3e55b ffff880215e8f520 ffffffff8104fc88 ffffffff8104fcab
  0000000915e88300 0000000000000046 ffffffffa019b29a 0000000000000001
 Call Trace:
  [<ffffffff812fc8e3>] dump_stack+0x67/0x90
  [<ffffffff8104fc88>] __warn+0xcb/0xe9
  [<ffffffff8104fcab>] ? warn_slowpath_null+0x5/0x1f
 ------------[ cut here ]------------
 WARNING: CPU: 1 PID: 0 at kernel/module.c:268 module_assert_mutex_or_preempt+0x3c/0x3e
[...]

Which gives us rather useless information. Worse yet, there's some race
that causes this, and I seldom trigger it, so I have no idea what
happened.

This would not be an issue if that warning was a WARN_ON_ONCE().

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2016-08-04 10:16:52 +09:30
Jakub Kicinski
1f415a74b0 bpf: fix method of PTR_TO_PACKET reg id generation
Using per-register incrementing ID can lead to
find_good_pkt_pointers() confusing registers which
have completely different values.  Consider example:

0: (bf) r6 = r1
1: (61) r8 = *(u32 *)(r6 +76)
2: (61) r0 = *(u32 *)(r6 +80)
3: (bf) r7 = r8
4: (07) r8 += 32
5: (2d) if r8 > r0 goto pc+9
 R0=pkt_end R1=ctx R6=ctx R7=pkt(id=0,off=0,r=32) R8=pkt(id=0,off=32,r=32) R10=fp
6: (bf) r8 = r7
7: (bf) r9 = r7
8: (71) r1 = *(u8 *)(r7 +0)
9: (0f) r8 += r1
10: (71) r1 = *(u8 *)(r7 +1)
11: (0f) r9 += r1
12: (07) r8 += 32
13: (2d) if r8 > r0 goto pc+1
 R0=pkt_end R1=inv56 R6=ctx R7=pkt(id=0,off=0,r=32) R8=pkt(id=1,off=32,r=32) R9=pkt(id=1,off=0,r=32) R10=fp
14: (71) r1 = *(u8 *)(r9 +16)
15: (b7) r7 = 0
16: (bf) r0 = r7
17: (95) exit

We need to get a UNKNOWN_VALUE with imm to force id
generation so lines 0-5 make r7 a valid packet pointer.
We then read two different bytes from the packet and
add them to copies of the constructed packet pointer.
r8 (line 9) and r9 (line 11) will get the same id of 1,
independently.  When either of them is validated (line
13) - find_good_pkt_pointers() will also mark the other
as safe.  This leads to access on line 14 being mistakenly
considered safe.

Fixes: 969bf05eb3 ("bpf: direct packet access")
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-08-03 11:53:33 -07:00
Linus Torvalds
bf0f500bd0 A few updates and fixes:
. Move the suppressing of the __builtin_return_address >0 warning to the
    tracing directory only.
 
  . metag recordmcount fix for newer glibc's
 
  . Two tracing histogram fixes that were reported by KASAN
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Merge tag 'trace-v4.8-1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing fixes from Steven Rostedt:
 "A few updates and fixes:

   - move the suppressing of the __builtin_return_address >0 warning to
     the tracing directory only.

   - metag recordmcount fix for newer glibc's

   - two tracing histogram fixes that were reported by KASAN"

* tag 'trace-v4.8-1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing: Fix use-after-free in hist_register_trigger()
  tracing: Fix use-after-free in hist_unreg_all/hist_enable_unreg_all
  Makefile: Mute warning for __builtin_return_address(>0) for tracing only
  ftrace/recordmcount: Work around for addition of metag magic but not relocations
2016-08-03 12:50:06 -04:00
Rob Herring
27eb6622ab config: add android config fragments
Copy the config fragments from the AOSP common kernel android-4.4
branch.  It is becoming possible to run mainline kernels with Android,
but the kernel defconfigs don't work as-is and debugging missing config
options is a pain.  Adding the config fragments into the kernel tree,
makes configuring a mainline kernel as simple as:

  make ARCH=arm multi_v7_defconfig android-base.config android-recommended.config

The following non-upstream config options were removed:

  CONFIG_NETFILTER_XT_MATCH_QTAGUID
  CONFIG_NETFILTER_XT_MATCH_QUOTA2
  CONFIG_NETFILTER_XT_MATCH_QUOTA2_LOG
  CONFIG_PPPOLAC
  CONFIG_PPPOPNS
  CONFIG_SECURITY_PERF_EVENTS_RESTRICT
  CONFIG_USB_CONFIGFS_F_MTP
  CONFIG_USB_CONFIGFS_F_PTP
  CONFIG_USB_CONFIGFS_F_ACC
  CONFIG_USB_CONFIGFS_F_AUDIO_SRC
  CONFIG_USB_CONFIGFS_UEVENT
  CONFIG_INPUT_KEYCHORD
  CONFIG_INPUT_KEYRESET

Link: http://lkml.kernel.org/r/1466708235-28593-1-git-send-email-robh@kernel.org
Signed-off-by: Rob Herring <robh@kernel.org>
Cc: Amit Pundir <amit.pundir@linaro.org>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Dmitry Shmidt <dimitrysh@google.com>
Cc: Rom Lemarchand <romlem@android.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-08-02 19:35:42 -04:00
Akash Goel
59dbb2a06f relay: add global mode support for buffer-only channels
Commit 20d8b67c06 ("relay: add buffer-only channels; useful for early
logging") added support to use channels with no associated files.

This is useful when the exact location of relay file is not known or the
the parent directory of relay file is not available, while creating the
channel and the logging has to start right from the boot.

But there was no provision to use global mode with buffer-only channels,
which is added by this patch, without modifying the interface where
initially there will be a dummy invocation of create_buf_file callback
through which kernel client can convey the need of a global buffer.

For the use case where drivers/kernel clients want a simple interface
for the userspace, which enables them to capture data/logs from relay
file inorder & without any post processing, support of Global buffer
mode is warranted.

Modules, like i915, using relay_open() in early init would have to later
register their buffer-only relays, once debugfs is available, by calling
relay_late_setup_files().  Hence relay_late_setup_files() symbol also
needs to be exported.

Link: http://lkml.kernel.org/r/1468404563-11653-1-git-send-email-akash.goel@intel.com
Signed-off-by: Akash Goel <akash.goel@intel.com>
Cc: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro>
Cc: Tom Zanussi <tzanussi@gmail.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-08-02 19:35:41 -04:00
zhong jiang
1730f14660 kexec: add restriction on kexec_load() segment sizes
I hit the following issue when run trinity in my system.  The kernel is
3.4 version, but mainline has the same issue.

The root cause is that the segment size is too large so the kerenl
spends too long trying to allocate a page.  Other cases will block until
the test case quits.  Also, OOM conditions will occur.

Call Trace:
  __alloc_pages_nodemask+0x14c/0x8f0
  alloc_pages_current+0xaf/0x120
  kimage_alloc_pages+0x10/0x60
  kimage_alloc_control_pages+0x5d/0x270
  machine_kexec_prepare+0xe5/0x6c0
  ? kimage_free_page_list+0x52/0x70
  sys_kexec_load+0x141/0x600
  ? vfs_write+0x100/0x180
  system_call_fastpath+0x16/0x1b

The patch changes sanity_check_segment_list() to verify that the usage by
all segments does not exceed half of memory.

[akpm@linux-foundation.org: fix for kexec-return-error-number-directly.patch, update comment]
Link: http://lkml.kernel.org/r/1469625474-53904-1-git-send-email-zhongjiang@huawei.com
Signed-off-by: zhong jiang <zhongjiang@huawei.com>
Suggested-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Dave Young <dyoung@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-08-02 19:35:31 -04:00
Petr Tesarik
21db79e8bb kexec: add a kexec_crash_loaded() function
Provide a wrapper function to be used by kernel code to check whether a
crash kernel is loaded.  It returns the same value that can be seen in
/sys/kernel/kexec_crash_loaded by userspace programs.

I'm exporting the function, because it will be used by Xen, and it is
possible to compile Xen modules separately to enable the use of PV
drivers with unmodified bare-metal kernels.

Link: http://lkml.kernel.org/r/20160713121955.14969.69080.stgit@hananiah.suse.cz
Signed-off-by: Petr Tesarik <ptesarik@suse.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: David Vrabel <david.vrabel@citrix.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-08-02 19:35:30 -04:00
Hidehiro Kawai
b26e27ddfd kexec: use core_param for crash_kexec_post_notifiers boot option
crash_kexec_post_notifiers ia a boot option which controls whether the
1st kernel calls panic notifiers or not before booting the 2nd kernel.
However, there is no need to limit it to being modifiable only at boot
time.  So, use core_param instead of early_param.

Link: http://lkml.kernel.org/r/20160705113327.5864.43139.stgit@softrs
Signed-off-by: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Borislav Petkov <bp@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-08-02 19:35:29 -04:00
Russell King
43546d8669 kexec: allow architectures to override boot mapping
kexec physical addresses are the boot-time view of the system.  For
certain ARM systems (such as Keystone 2), the boot view of the system
does not match the kernel's view of the system: the boot view uses a
special alias in the lower 4GB of the physical address space.

To cater for these kinds of setups, we need to translate between the
boot view physical addresses and the normal kernel view physical
addresses.  This patch extracts the current transation points into
linux/kexec.h, and allows an architecture to override the functions.

Due to the translations required, we unfortunately end up with six
translation functions, which are reduced down to four that the
architecture can override.

[akpm@linux-foundation.org: kexec.h needs asm/io.h for phys_to_virt()]
Link: http://lkml.kernel.org/r/E1b8koP-0004HZ-Vf@rmk-PC.armlinux.org.uk
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: Keerthy <j-keerthy@ti.com>
Cc: Pratyush Anand <panand@redhat.com>
Cc: Vitaly Andrianov <vitalya@ti.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Simon Horman <horms@verge.net.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-08-02 19:35:27 -04:00
Russell King
dae28018f5 kdump: arrange for paddr_vmcoreinfo_note() to return phys_addr_t
On PAE systems (eg, ARM LPAE) the vmcore note may be located above 4GB
physical on 32-bit architectures, so we need a wider type than "unsigned
long" here.  Arrange for paddr_vmcoreinfo_note() to return a
phys_addr_t, thereby allowing it to be located above 4GB.

This makes no difference for kexec-tools, as they already assume a
64-bit type when reading from this file.

Link: http://lkml.kernel.org/r/E1b8koK-0004HS-K9@rmk-PC.armlinux.org.uk
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Reviewed-by: Pratyush Anand <panand@redhat.com>
Acked-by: Baoquan He <bhe@redhat.com>
Cc: Keerthy <j-keerthy@ti.com>
Cc: Vitaly Andrianov <vitalya@ti.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Simon Horman <horms@verge.net.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-08-02 19:35:27 -04:00
Russell King
465d377701 kexec: ensure user memory sizes do not wrap
Ensure that user memory sizes do not wrap around when validating the
user input, which can lead to the following input validation working
incorrectly.

[akpm@linux-foundation.org: fix it for kexec-return-error-number-directly.patch]
Link: http://lkml.kernel.org/r/E1b8koF-0004HM-5x@rmk-PC.armlinux.org.uk
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Reviewed-by: Pratyush Anand <panand@redhat.com>
Acked-by: Baoquan He <bhe@redhat.com>
Cc: Keerthy <j-keerthy@ti.com>
Cc: Vitaly Andrianov <vitalya@ti.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Simon Horman <horms@verge.net.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-08-02 19:35:26 -04:00
Minfei Huang
4caf961524 kexec: return error number directly
This is a cleanup patch to make kexec more clear to return error number
directly.  The variable result is useless, because there is no other
function's return value assignes to it.  So remove it.

Link: http://lkml.kernel.org/r/1464179273-57668-1-git-send-email-mnghuan@gmail.com
Signed-off-by: Minfei Huang <mnghuan@gmail.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Xunlei Pang <xlpang@redhat.com>
Cc: Atsushi Kumagai <ats-kumagai@wm.jp.nec.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-08-02 19:35:24 -04:00
Anton Blanchard
627393d448 kernel/exit.c: quieten greatest stack depth printk
Many targets enable CONFIG_DEBUG_STACK_USAGE, and while the information
is useful, it isn't worthy of pr_warn().  Reduce it to pr_info().

Link: http://lkml.kernel.org/r/1466982072-29836-1-git-send-email-anton@ozlabs.org
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-08-02 19:35:23 -04:00
Borislav Petkov
750afe7bab printk: add kernel parameter to control writes to /dev/kmsg
Add a "printk.devkmsg" kernel command line parameter which controls how
userspace writes into /dev/kmsg.  It has three options:

 * ratelimit - ratelimit logging from userspace.
 * on  - unlimited logging from userspace
 * off - logging from userspace gets ignored

The default setting is to ratelimit the messages written to it.

This changes the kernel default setting of "on" to "ratelimit" and we do
that because we want to keep userspace spamming /dev/kmsg to sane
levels.  This is especially moot when a small kernel log buffer wraps
around and messages get lost.  So the ratelimiting setting should be a
sane setting where kernel messages should have a bit higher chance of
survival from all the spamming.

It additionally does not limit logging to /dev/kmsg while the system is
booting if we haven't disabled it on the command line.

Furthermore, we can control the logging from a lower priority sysctl
interface - kernel.printk_devkmsg.

That interface will succeed only if printk.devkmsg *hasn't* been
supplied on the command line.  If it has, then printk.devkmsg is a
one-time setting which remains for the duration of the system lifetime.
This "locking" of the setting is to prevent userspace from changing the
logging on us through sysctl(2).

This patch is based on previous patches from Linus and Steven.

[bp@suse.de: fixes]
  Link: http://lkml.kernel.org/r/20160719072344.GC25563@nazgul.tnic
Link: http://lkml.kernel.org/r/20160716061745.15795-3-bp@alien8.de
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Dave Young <dyoung@redhat.com>
Cc: Franck Bui <fbui@suse.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-08-02 19:35:06 -04:00
Christoph Hellwig
40a7d9f5f9 printk: include <asm/sections.h> instead of <asm-generic/sections.h>
asm-generic headers are generic implementations for architecture
specific code and should not be included by common code.  Thus use the
asm/ version of sections.h to get at the linker sections.

Link: http://lkml.kernel.org/r/1468285008-7331-1-git-send-email-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-08-02 19:35:05 -04:00
Sergey Senozhatsky
cf7754441c printk: introduce suppress_message_printing()
Messages' levels and console log level are inspected when the actual
printing occurs, which may provoke console_unlock() and
console_cont_flush() to waste CPU cycles on every message that has
loglevel above the current console_loglevel.

Schematically, console_unlock() does the following:

console_unlock()
{
        ...
        for (;;) {
                ...
                raw_spin_lock_irqsave(&logbuf_lock, flags);
skip:
                msg = log_from_idx(console_idx);

                if (msg->flags & LOG_NOCONS) {
                        ...
                        goto skip;
                }

                level = msg->level;
                len += msg_print_text();                        >> sprintfs
                                                                   memcpy,
                                                                   etc.

                if (nr_ext_console_drivers) {
                        ext_len = msg_print_ext_header();       >> scnprintf
                        ext_len += msg_print_ext_body();        >> scnprintfs
                                                                   etc.
                }
                ...
                raw_spin_unlock(&logbuf_lock);

                call_console_drivers(level, ext_text, ext_len, text, len)
                {
                        if (level >= console_loglevel &&        >> drop the message
                                        !ignore_loglevel)
                                return;

                        console->write(...);
                }

                local_irq_restore(flags);
        }
        ...
}

The thing here is this deferred `level >= console_loglevel' check.  We
are wasting CPU cycles on sprintfs/memcpy/etc.  preparing the messages
that we will eventually drop.

This can be huge when we register a new CON_PRINTBUFFER console, for
instance.  For every such a console register_console() resets the

        console_seq, console_idx, console_prev

and sets a `exclusive console' pointer to replay the log buffer to that
just-registered console.  And there can be a lot of messages to replay,
in the worst case most of which can be dropped after console_loglevel
test.

We know messages' levels long before we call msg_print_text() and
friends, so we can just move console_loglevel check out of
call_console_drivers() and format a new message only if we are sure that
it won't be dropped.

The patch factors out loglevel check into suppress_message_printing()
function and tests message->level and console_loglevel before formatting
functions in console_unlock() and console_cont_flush() are getting
executed.  This improves things not only for exclusive CON_PRINTBUFFER
consoles, but for every console_unlock() that attempts to print a
message of level above the console_loglevel.

Link: http://lkml.kernel.org/r/20160627135012.8229-1-sergey.senozhatsky@gmail.com
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Calvin Owens <calvinowens@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-08-02 19:35:04 -04:00
Joe Perches
874f9c7da9 printk: create pr_<level> functions
Using functions instead of macros can reduce overall code size by
eliminating unnecessary "KERN_SOH<digit>" prefixes from format strings.

  defconfig x86-64:

  $ size vmlinux*
     text    data     bss      dec     hex  filename
  10193570 4331464 1105920 15630954  ee826a vmlinux.new
  10192623 4335560 1105920 15634103  ee8eb7 vmlinux.old

As the return value are unimportant and unused in the kernel tree, these
new functions return void.

Miscellanea:

 - change pr_<level> macros to call new __pr_<level> functions
 - change vprintk_nmi and vprintk_default to add LOGLEVEL_<level> argument

[akpm@linux-foundation.org: fix LOGLEVEL_INFO, per Joe]
Link: http://lkml.kernel.org/r/e16cc34479dfefcae37c98b481e6646f0f69efc3.1466718827.git.joe@perches.com
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-08-02 19:35:04 -04:00
Sergey Senozhatsky
bebca05281 printk: do not include interrupt.h
A trivial cosmetic change: interrupt.h header is redundant since commit
6b898c07cb ("console: use might_sleep in console_lock").

Link: http://lkml.kernel.org/r/20160620132847.21930-1-sergey.senozhatsky@gmail.com
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-08-02 19:35:03 -04:00
Luis de Bethencourt
9d5059c959 dynamic_debug: only add header when used
kernel.h header doesn't directly use dynamic debug, instead we can
include it in module.c (which used it via kernel.h).  printk.h only uses
it if CONFIG_DYNAMIC_DEBUG is on, changing the inclusion to only happen
in that case.

Link: http://lkml.kernel.org/r/1468429793-16917-1-git-send-email-luisbg@osg.samsung.com
[luisbg@osg.samsung.com: include dynamic_debug.h in drb_int.h]
  Link: http://lkml.kernel.org/r/1468447828-18558-2-git-send-email-luisbg@osg.samsung.com
Signed-off-by: Luis de Bethencourt <luisbg@osg.samsung.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-08-02 19:35:03 -04:00
Oleg Nesterov
61e96496d3 task_work: use READ_ONCE/lockless_dereference, avoid pi_lock if !task_works
Change task_work_cancel() to use lockless_dereference(), this is what
the code really wants but we didn't have this helper when it was
written.

Also add the fast-path task->task_works == NULL check, in the likely
case this task has no pending works and we can avoid
spin_lock(task->pi_lock).

While at it, change other users of ACCESS_ONCE() to use READ_ONCE().

Link: http://lkml.kernel.org/r/20160610150042.GA13868@redhat.com
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Andrea Parri <parri.andrea@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-08-02 19:35:02 -04:00
Tom Zanussi
7522c03ae3 tracing: Fix use-after-free in hist_register_trigger()
This fixes a use-after-free case flagged by KASAN; make sure the test
happens before the potential free in this case.

Link: http://lkml.kernel.org/r/48fd74ab61bebd7dca9714386bb47d7c5ccd6a7b.1467247517.git.tom.zanussi@linux.intel.com

Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-08-02 15:16:30 -04:00
Steven Rostedt
47c1856971 tracing: Fix use-after-free in hist_unreg_all/hist_enable_unreg_all
While running tools/testing/selftests test suite with KASAN, Dmitry
Vyukov hit the following use-after-free report:

  ==================================================================
  BUG: KASAN: use-after-free in hist_unreg_all+0x1a1/0x1d0 at addr
  ffff880031632cc0
  Read of size 8 by task ftracetest/7413
  ==================================================================
  BUG kmalloc-128 (Not tainted): kasan: bad access detected
  ------------------------------------------------------------------

This fixes the problem, along with the same problem in
hist_enable_unreg_all().

Link: http://lkml.kernel.org/r/c3d05b79e42555b6e36a3a99aae0e37315ee5304.1467247517.git.tom.zanussi@linux.intel.com

Cc: Dmitry Vyukov <dvyukov@google.com>
[Copied Steve's hist_enable_unreg_all() fix to hist_unreg_all()]
Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-08-02 15:16:02 -04:00
Steven Rostedt
377ccbb483 Makefile: Mute warning for __builtin_return_address(>0) for tracing only
With the latest gcc compilers, they give a warning if
__builtin_return_address() parameter is greater than 0. That is because if
it is used by a function called by a top level function (or in the case of
the kernel, by assembly), it can try to access stack frames outside the
stack and crash the system.

The tracing system uses __builtin_return_address() of up to 2! But it is
well aware of the dangers that it may have, and has even added precautions
to protect against it (see the thunk code in arch/x86/entry/thunk*.S)

Linus originally added KBUILD_CFLAGS that would suppress the warning for the
entire kernel, as simply adding KBUILD_CFLAGS to the tracing directory
wouldn't work. The tracing directory plays a bit with the CFLAGS and
requires a little more logic.

This adds that special logic to only suppress the warning for the tracing
directory. If it is used anywhere else outside of tracing, the warning will
still be triggered.

Link: http://lkml.kernel.org/r/20160728223043.51996267@grimm.local.home

Tested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-08-02 12:57:48 -04:00
David Ahern
0d87d7ec22 perf/core: Change log level for duration warning to KERN_INFO
When the perf interrupt handler exceeds a threshold warning messages
are displayed on console:

  [12739.31793] perf interrupt took too long (2504 > 2500), lowering kernel.perf_event_max_sample_rate to 50000
  [71340.165065] perf interrupt took too long (5005 > 5000), lowering kernel.perf_event_max_sample_rate to 25000

Many customers and users are confused by the message wondering if
something is wrong or they need to take action to fix a problem.
Since a user can not do anything to fix the issue, the message is really
more informational than a warning. Adjust the log level accordingly.

Signed-off-by: David Ahern <dsa@cumulusnetworks.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1470084569-438-1-git-send-email-dsa@cumulusnetworks.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-02 10:23:57 +02:00
Kevin Hao
e3f91083fa jump_label: Make it possible for arches to invoke jump_label_init() earlier
Some arches (powerpc at least) would like to invoke jump_label_init()
much earlier in boot. So check static_key_initialized in order to make
sure this function runs only once.

LGTM-by: Ingo (http://marc.info/?l=linux-kernel&m=144049104329961&w=2)
Signed-off-by: Kevin Hao <haokexin@gmail.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-08-01 11:15:01 +10:00
Linus Torvalds
228ffba23e Merge branch 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull misc fixes from Thomas Gleixner:
 "This update contains:

   - a fix for stomp-machine so the nmi_watchdog wont trigger on the cpu
     waiting for the others to execute the callback

   - various fixes and updates to objtool including an resync of the
     instruction decoder to match the kernel's decoder"

* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  objtool: Un-capitalize "Warning" for out-of-sync instruction decoder
  objtool: Resync x86 instruction decoder with the kernel's
  objtool: Support new GCC 6 switch jump table pattern
  stop_machine: Touch_nmi_watchdog() after MULTI_STOP_PREPARE
  objtool: Add 'fixdep' to objtool/.gitignore
2016-07-30 11:54:53 -07:00
Linus Torvalds
797cee982e Merge branch 'stable-4.8' of git://git.infradead.org/users/pcmoore/audit
Pull audit updates from Paul Moore:
 "Six audit patches for 4.8.

  There are a couple of style and minor whitespace tweaks for the logs,
  as well as a minor fixup to catch errors on user filter rules, however
  the major improvements are a fix to the s390 syscall argument masking
  code (reviewed by the nice s390 folks), some consolidation around the
  exclude filtering (less code, always a win), and a double-fetch fix
  for recording the execve arguments"

* 'stable-4.8' of git://git.infradead.org/users/pcmoore/audit:
  audit: fix a double fetch in audit_log_single_execve_arg()
  audit: fix whitespace in CWD record
  audit: add fields to exclude filter by reusing user filter
  s390: ensure that syscall arguments are properly masked on s390
  audit: fix some horrible switch statement style crimes
  audit: fixup: log on errors from filter user rules
2016-07-29 17:54:17 -07:00
Linus Torvalds
7a1e8b80fb Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security
Pull security subsystem updates from James Morris:
 "Highlights:

   - TPM core and driver updates/fixes
   - IPv6 security labeling (CALIPSO)
   - Lots of Apparmor fixes
   - Seccomp: remove 2-phase API, close hole where ptrace can change
     syscall #"

* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: (156 commits)
  apparmor: fix SECURITY_APPARMOR_HASH_DEFAULT parameter handling
  tpm: Add TPM 2.0 support to the Nuvoton i2c driver (NPCT6xx family)
  tpm: Factor out common startup code
  tpm: use devm_add_action_or_reset
  tpm2_i2c_nuvoton: add irq validity check
  tpm: read burstcount from TPM_STS in one 32-bit transaction
  tpm: fix byte-order for the value read by tpm2_get_tpm_pt
  tpm_tis_core: convert max timeouts from msec to jiffies
  apparmor: fix arg_size computation for when setprocattr is null terminated
  apparmor: fix oops, validate buffer size in apparmor_setprocattr()
  apparmor: do not expose kernel stack
  apparmor: fix module parameters can be changed after policy is locked
  apparmor: fix oops in profile_unpack() when policy_db is not present
  apparmor: don't check for vmalloc_addr if kvzalloc() failed
  apparmor: add missing id bounds check on dfa verification
  apparmor: allow SYS_CAP_RESOURCE to be sufficient to prlimit another task
  apparmor: use list_next_entry instead of list_entry_next
  apparmor: fix refcount race when finding a child profile
  apparmor: fix ref count leak when profile sha1 hash is read
  apparmor: check that xindex is in trans_table bounds
  ...
2016-07-29 17:38:46 -07:00
Linus Torvalds
a867d7349e Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull userns vfs updates from Eric Biederman:
 "This tree contains some very long awaited work on generalizing the
  user namespace support for mounting filesystems to include filesystems
  with a backing store.  The real world target is fuse but the goal is
  to update the vfs to allow any filesystem to be supported.  This
  patchset is based on a lot of code review and testing to approach that
  goal.

  While looking at what is needed to support the fuse filesystem it
  became clear that there were things like xattrs for security modules
  that needed special treatment.  That the resolution of those concerns
  would not be fuse specific.  That sorting out these general issues
  made most sense at the generic level, where the right people could be
  drawn into the conversation, and the issues could be solved for
  everyone.

  At a high level what this patchset does a couple of simple things:

   - Add a user namespace owner (s_user_ns) to struct super_block.

   - Teach the vfs to handle filesystem uids and gids not mapping into
     to kuids and kgids and being reported as INVALID_UID and
     INVALID_GID in vfs data structures.

  By assigning a user namespace owner filesystems that are mounted with
  only user namespace privilege can be detected.  This allows security
  modules and the like to know which mounts may not be trusted.  This
  also allows the set of uids and gids that are communicated to the
  filesystem to be capped at the set of kuids and kgids that are in the
  owning user namespace of the filesystem.

  One of the crazier corner casees this handles is the case of inodes
  whose i_uid or i_gid are not mapped into the vfs.  Most of the code
  simply doesn't care but it is easy to confuse the inode writeback path
  so no operation that could cause an inode write-back is permitted for
  such inodes (aka only reads are allowed).

  This set of changes starts out by cleaning up the code paths involved
  in user namespace permirted mounts.  Then when things are clean enough
  adds code that cleanly sets s_user_ns.  Then additional restrictions
  are added that are possible now that the filesystem superblock
  contains owner information.

  These changes should not affect anyone in practice, but there are some
  parts of these restrictions that are changes in behavior.

   - Andy's restriction on suid executables that does not honor the
     suid bit when the path is from another mount namespace (think
     /proc/[pid]/fd/) or when the filesystem was mounted by a less
     privileged user.

   - The replacement of the user namespace implicit setting of MNT_NODEV
     with implicitly setting SB_I_NODEV on the filesystem superblock
     instead.

     Using SB_I_NODEV is a stronger form that happens to make this state
     user invisible.  The user visibility can be managed but it caused
     problems when it was introduced from applications reasonably
     expecting mount flags to be what they were set to.

  There is a little bit of work remaining before it is safe to support
  mounting filesystems with backing store in user namespaces, beyond
  what is in this set of changes.

   - Verifying the mounter has permission to read/write the block device
     during mount.

   - Teaching the integrity modules IMA and EVM to handle filesystems
     mounted with only user namespace root and to reduce trust in their
     security xattrs accordingly.

   - Capturing the mounters credentials and using that for permission
     checks in d_automount and the like.  (Given that overlayfs already
     does this, and we need the work in d_automount it make sense to
     generalize this case).

  Furthermore there are a few changes that are on the wishlist:

   - Get all filesystems supporting posix acls using the generic posix
     acls so that posix_acl_fix_xattr_from_user and
     posix_acl_fix_xattr_to_user may be removed.  [Maintainability]

   - Reducing the permission checks in places such as remount to allow
     the superblock owner to perform them.

   - Allowing the superblock owner to chown files with unmapped uids and
     gids to something that is mapped so the files may be treated
     normally.

  I am not considering even obvious relaxations of permission checks
  until it is clear there are no more corner cases that need to be
  locked down and handled generically.

  Many thanks to Seth Forshee who kept this code alive, and putting up
  with me rewriting substantial portions of what he did to handle more
  corner cases, and for his diligent testing and reviewing of my
  changes"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (30 commits)
  fs: Call d_automount with the filesystems creds
  fs: Update i_[ug]id_(read|write) to translate relative to s_user_ns
  evm: Translate user/group ids relative to s_user_ns when computing HMAC
  dquot: For now explicitly don't support filesystems outside of init_user_ns
  quota: Handle quota data stored in s_user_ns in quota_setxquota
  quota: Ensure qids map to the filesystem
  vfs: Don't create inodes with a uid or gid unknown to the vfs
  vfs: Don't modify inodes with a uid or gid unknown to the vfs
  cred: Reject inodes with invalid ids in set_create_file_as()
  fs: Check for invalid i_uid in may_follow_link()
  vfs: Verify acls are valid within superblock's s_user_ns.
  userns: Handle -1 in k[ug]id_has_mapping when !CONFIG_USER_NS
  fs: Refuse uid/gid changes which don't map into s_user_ns
  selinux: Add support for unprivileged mounts from user namespaces
  Smack: Handle labels consistently in untrusted mounts
  Smack: Add support for unprivileged mounts from user namespaces
  fs: Treat foreign mounts as nosuid
  fs: Limit file caps to the user namespace of the super block
  userns: Remove the now unnecessary FS_USERNS_DEV_MOUNT flag
  userns: Remove implicit MNT_NODEV fragility.
  ...
2016-07-29 15:54:19 -07:00
Linus Torvalds
574c7e2333 Merge branch 'for-4.7-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull more cgroup updates from Tejun Heo:
 "I forgot to include the patches which got applied to for-4.7-fixes
  late during last cycle.

  Eric's three patches fix bugs introduced with the namespace support"

* 'for-4.7-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  cgroupns: Only allow creation of hierarchies in the initial cgroup namespace
  cgroupns: Close race between cgroup_post_fork and copy_cgroup_ns
  cgroupns: Fix the locking in copy_cgroup_ns
2016-07-29 14:29:04 -07:00
Linus Torvalds
a6408f6cb6 Merge branch 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull smp hotplug updates from Thomas Gleixner:
 "This is the next part of the hotplug rework.

   - Convert all notifiers with a priority assigned

   - Convert all CPU_STARTING/DYING notifiers

     The final removal of the STARTING/DYING infrastructure will happen
     when the merge window closes.

  Another 700 hundred line of unpenetrable maze gone :)"

* 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (70 commits)
  timers/core: Correct callback order during CPU hot plug
  leds/trigger/cpu: Move from CPU_STARTING to ONLINE level
  powerpc/numa: Convert to hotplug state machine
  arm/perf: Fix hotplug state machine conversion
  irqchip/armada: Avoid unused function warnings
  ARC/time: Convert to hotplug state machine
  clocksource/atlas7: Convert to hotplug state machine
  clocksource/armada-370-xp: Convert to hotplug state machine
  clocksource/exynos_mct: Convert to hotplug state machine
  clocksource/arm_global_timer: Convert to hotplug state machine
  rcu: Convert rcutree to hotplug state machine
  KVM/arm/arm64/vgic-new: Convert to hotplug state machine
  smp/cfd: Convert core to hotplug state machine
  x86/x2apic: Convert to CPU hotplug state machine
  profile: Convert to hotplug state machine
  timers/core: Convert to hotplug state machine
  hrtimer: Convert to hotplug state machine
  x86/tboot: Convert to hotplug state machine
  arm64/armv8 deprecated: Convert to hotplug state machine
  hwtracing/coresight-etm4x: Convert to hotplug state machine
  ...
2016-07-29 13:55:30 -07:00
Thomas Gleixner
784bdf3bb6 futex: Assume all mappings are private on !MMU systems
To quote Rick why there is no need for shared mapping on !MMU systems:

|With MMU, shared futex keys need to identify the physical backing for
|a memory address because it may be mapped at different addresses in
|different processes (or even multiple times in the same process).
|Without MMU this cannot happen. You only have physical addresses. So
|the "private futex" behavior of using the virtual address as the key
|is always correct (for both shared and private cases) on nommu
|systems.

This patch disables the FLAGS_SHARED in a way that allows the compiler to
remove that code.

[bigeasy: Added changelog ]
Reported-by: Rich Felker <dalias@libc.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20160729143230.GA21715@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-07-29 18:44:14 +02:00
Linus Torvalds
c624c86615 This is mostly clean ups and small fixes. Some of the more visible
changes are:
 
  . The function pid code uses the event pid filtering logic
  . [ku]probe events have access to current->comm
  . trace_printk now has sample code
  . PCI devices now trace physical addresses
  . stack tracing has less unnessary functions traced
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Merge tag 'trace-v4.8' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing updates from Steven Rostedt:
 "This is mostly clean ups and small fixes.  Some of the more visible
  changes are:

   - The function pid code uses the event pid filtering logic
   - [ku]probe events have access to current->comm
   - trace_printk now has sample code
   - PCI devices now trace physical addresses
   - stack tracing has less unnessary functions traced"

* tag 'trace-v4.8' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  printk, tracing: Avoiding unneeded blank lines
  tracing: Use __get_str() when manipulating strings
  tracing, RAS: Cleanup on __get_str() usage
  tracing: Use outer () on __get_str() definition
  ftrace: Reduce size of function graph entries
  tracing: Have HIST_TRIGGERS select TRACING
  tracing: Using for_each_set_bit() to simplify trace_pid_write()
  ftrace: Move toplevel init out of ftrace_init_tracefs()
  tracing/function_graph: Fix filters for function_graph threshold
  tracing: Skip more functions when doing stack tracing of events
  tracing: Expose CPU physical addresses (resource values) for PCI devices
  tracing: Show the preempt count of when the event was called
  tracing: Add trace_printk sample code
  tracing: Choose static tp_printk buffer by explicit nesting count
  tracing: expose current->comm to [ku]probe events
  ftrace: Have set_ftrace_pid use the bitmap like events do
  tracing: Move pid_list write processing into its own function
  tracing: Move the pid_list seq_file functions to be global
  tracing: Move filtered_pid helper functions into trace.c
  tracing: Make the pid filtering helper functions global
2016-07-28 18:20:09 -07:00
Linus Torvalds
f0c98ebc57 libnvdimm for 4.8
1/ Replace pcommit with ADR / directed-flushing:
    The pcommit instruction, which has not shipped on any product, is
    deprecated. Instead, the requirement is that platforms implement either
    ADR, or provide one or more flush addresses per nvdimm. ADR
    (Asynchronous DRAM Refresh) flushes data in posted write buffers to the
    memory controller on a power-fail event. Flush addresses are defined in
    ACPI 6.x as an NVDIMM Firmware Interface Table (NFIT) sub-structure:
    "Flush Hint Address Structure". A flush hint is an mmio address that
    when written and fenced assures that all previous posted writes
    targeting a given dimm have been flushed to media.
 
 2/ On-demand ARS (address range scrub):
    Linux uses the results of the ACPI ARS commands to track bad blocks
    in pmem devices.  When latent errors are detected we re-scrub the media
    to refresh the bad block list, userspace can also request a re-scrub at
    any time.
 
 3/ Support for the Microsoft DSM (device specific method) command format.
 
 4/ Support for EDK2/OVMF virtual disk device memory ranges.
 
 5/ Various fixes and cleanups across the subsystem.
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Merge tag 'libnvdimm-for-4.8' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm

Pull libnvdimm updates from Dan Williams:

 - Replace pcommit with ADR / directed-flushing.

   The pcommit instruction, which has not shipped on any product, is
   deprecated.  Instead, the requirement is that platforms implement
   either ADR, or provide one or more flush addresses per nvdimm.

   ADR (Asynchronous DRAM Refresh) flushes data in posted write buffers
   to the memory controller on a power-fail event.

   Flush addresses are defined in ACPI 6.x as an NVDIMM Firmware
   Interface Table (NFIT) sub-structure: "Flush Hint Address Structure".
   A flush hint is an mmio address that when written and fenced assures
   that all previous posted writes targeting a given dimm have been
   flushed to media.

 - On-demand ARS (address range scrub).

   Linux uses the results of the ACPI ARS commands to track bad blocks
   in pmem devices.  When latent errors are detected we re-scrub the
   media to refresh the bad block list, userspace can also request a
   re-scrub at any time.

 - Support for the Microsoft DSM (device specific method) command
   format.

 - Support for EDK2/OVMF virtual disk device memory ranges.

 - Various fixes and cleanups across the subsystem.

* tag 'libnvdimm-for-4.8' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm: (41 commits)
  libnvdimm-btt: Delete an unnecessary check before the function call "__nd_device_register"
  nfit: do an ARS scrub on hitting a latent media error
  nfit: move to nfit/ sub-directory
  nfit, libnvdimm: allow an ARS scrub to be triggered on demand
  libnvdimm: register nvdimm_bus devices with an nd_bus driver
  pmem: clarify a debug print in pmem_clear_poison
  x86/insn: remove pcommit
  Revert "KVM: x86: add pcommit support"
  nfit, tools/testing/nvdimm/: unify shutdown paths
  libnvdimm: move ->module to struct nvdimm_bus_descriptor
  nfit: cleanup acpi_nfit_init calling convention
  nfit: fix _FIT evaluation memory leak + use after free
  tools/testing/nvdimm: add manufacturing_{date|location} dimm properties
  tools/testing/nvdimm: add virtual ramdisk range
  acpi, nfit: treat virtual ramdisk SPA as pmem region
  pmem: kill __pmem address space
  pmem: kill wmb_pmem()
  libnvdimm, pmem: use nvdimm_flush() for namespace I/O writes
  fs/dax: remove wmb_pmem()
  libnvdimm, pmem: flush posted-write queues on shutdown
  ...
2016-07-28 17:38:16 -07:00
Andy Lutomirski
8b70ca6561 printk: when dumping regs, show the stack, not thread_info
We currently show:

  task: <current> ti: <current_thread_info()> task.ti: <task_thread_info(current)>"

"ti" and "task.ti" are redundant, and neither is actually what we want
to show, which the the base of the thread stack.  Change the display to
show the stack pointer explicitly.

Link: http://lkml.kernel.org/r/543ac5bd66ff94000a57a02e11af7239571a3055.1468523549.git.luto@kernel.org
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-07-28 16:07:41 -07:00
Andy Lutomirski
efdc949079 mm: fix memcg stack accounting for sub-page stacks
We should account for stacks regardless of stack size, and we need to
account in sub-page units if THREAD_SIZE < PAGE_SIZE.  Change the units
to kilobytes and Move it into account_kernel_stack().

Fixes: 12580e4b54 ("mm: memcontrol: report kernel stack usage in cgroup2 memory.stat")
Link: http://lkml.kernel.org/r/9b5314e3ee5eda61b0317ec1563768602c1ef438.1468523549.git.luto@kernel.org
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Vladimir Davydov <vdavydov@virtuozzo.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Reviewed-by: Vladimir Davydov <vdavydov@virtuozzo.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-07-28 16:07:41 -07:00
Andy Lutomirski
d30dd8be06 mm: track NR_KERNEL_STACK in KiB instead of number of stacks
Currently, NR_KERNEL_STACK tracks the number of kernel stacks in a zone.
This only makes sense if each kernel stack exists entirely in one zone,
and allowing vmapped stacks could break this assumption.

Since frv has THREAD_SIZE < PAGE_SIZE, we need to track kernel stack
allocations in a unit that divides both THREAD_SIZE and PAGE_SIZE on all
architectures.  Keep it simple and use KiB.

Link: http://lkml.kernel.org/r/083c71e642c5fa5f1b6898902e1b2db7b48940d4.1468523549.git.luto@kernel.org
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Vladimir Davydov <vdavydov@virtuozzo.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Reviewed-by: Vladimir Davydov <vdavydov@virtuozzo.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-07-28 16:07:41 -07:00
Dan Williams
11db048643 mm: cleanup ifdef guards for vmem_altmap
Now that ZONE_DEVICE depends on SPARSEMEM_VMEMMAP we can simplify some
ifdef guards to just ZONE_DEVICE.

Link: http://lkml.kernel.org/r/146687646788.39261.8020536391978771940.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Reported-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Eric Sandeen <sandeen@redhat.com>
Cc: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-07-28 16:07:41 -07:00
Mel Gorman
a5f5f91da6 mm: convert zone_reclaim to node_reclaim
As reclaim is now per-node based, convert zone_reclaim to be
node_reclaim.  It is possible that a node will be reclaimed multiple
times if it has multiple zones but this is unavoidable without caching
all nodes traversed so far.  The documentation and interface to
userspace is the same from a configuration perspective and will will be
similar in behaviour unless the node-local allocation requests were also
limited to lower zones.

Link: http://lkml.kernel.org/r/1467970510-21195-24-git-send-email-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Rik van Riel <riel@surriel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-07-28 16:07:41 -07:00
Mel Gorman
599d0c954f mm, vmscan: move LRU lists to node
This moves the LRU lists from the zone to the node and related data such
as counters, tracing, congestion tracking and writeback tracking.

Unfortunately, due to reclaim and compaction retry logic, it is
necessary to account for the number of LRU pages on both zone and node
logic.  Most reclaim logic is based on the node counters but the retry
logic uses the zone counters which do not distinguish inactive and
active sizes.  It would be possible to leave the LRU counters on a
per-zone basis but it's a heavier calculation across multiple cache
lines that is much more frequent than the retry checks.

Other than the LRU counters, this is mostly a mechanical patch but note
that it introduces a number of anomalies.  For example, the scans are
per-zone but using per-node counters.  We also mark a node as congested
when a zone is congested.  This causes weird problems that are fixed
later but is easier to review.

In the event that there is excessive overhead on 32-bit systems due to
the nodes being on LRU then there are two potential solutions

1. Long-term isolation of highmem pages when reclaim is lowmem

   When pages are skipped, they are immediately added back onto the LRU
   list. If lowmem reclaim persisted for long periods of time, the same
   highmem pages get continually scanned. The idea would be that lowmem
   keeps those pages on a separate list until a reclaim for highmem pages
   arrives that splices the highmem pages back onto the LRU. It potentially
   could be implemented similar to the UNEVICTABLE list.

   That would reduce the skip rate with the potential corner case is that
   highmem pages have to be scanned and reclaimed to free lowmem slab pages.

2. Linear scan lowmem pages if the initial LRU shrink fails

   This will break LRU ordering but may be preferable and faster during
   memory pressure than skipping LRU pages.

Link: http://lkml.kernel.org/r/1467970510-21195-4-git-send-email-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Rik van Riel <riel@surriel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-07-28 16:07:41 -07:00
Michal Hocko
fec1e5f987 cpuset, mm: fix TIF_MEMDIE check in cpuset_change_task_nodemask
Commit c0ff7453bb ("cpuset,mm: fix no node to alloc memory when
changing cpuset's mems") has added TIF_MEMDIE and PF_EXITING check but
it is checking the flag on the current task rather than the given one.

This doesn't make much sense and it is actually wrong.  If the current
task which updates the nodemask of a cpuset got killed by the OOM killer
then a part of the cpuset cgroup processes would have incompatible
nodemask which is surprising to say the least.

The comment suggests the intention was to skip oom victim or an exiting
task so we should be checking the given task.  But even then it would be
layering violation because it is the memory allocator to interpret the
TIF_MEMDIE meaning.  Simply drop both checks.  All tasks in the cpuset
should simply follow the same mask.

Link: http://lkml.kernel.org/r/1467029719-17602-3-git-send-email-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Miao Xie <miaox@cn.fujitsu.com>
Cc: Miao Xie <miaoxie@huawei.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-07-28 16:07:41 -07:00
Michal Hocko
a34c80a729 freezer, oom: check TIF_MEMDIE on the correct task
freezing_slow_path() is checking TIF_MEMDIE to skip OOM killed tasks.
It is, however, checking the flag on the current task rather than the
given one.  This is really confusing because freezing() can be called
also on !current tasks.  It would end up working correctly for its main
purpose because __refrigerator will be always called on the current task
so the oom victim will never get frozen.  But it could lead to
surprising results when a task which is freezing a cgroup got oom killed
because only part of the cgroup would get frozen.  This is highly
unlikely but worth fixing as the resulting code would be more clear
anyway.

Link: http://lkml.kernel.org/r/1467029719-17602-2-git-send-email-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Miao Xie <miaox@cn.fujitsu.com>
Cc: Miao Xie <miaoxie@huawei.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-07-28 16:07:41 -07:00
Richard Cochran
4fae16dffb timers/core: Correct callback order during CPU hot plug
On the tear-down path, the dead CPU callback for the timers was
misplaced within the 'cpuhp_state' enumeration.  There is a hidden
dependency between the timers and block multiqueue.  The timers
callback must happen before the block multiqueue callback otherwise a
RCU stall occurs.

Move the timers callback to the proper place in the state machine.

Reported-and-tested-by: Jon Hunter <jonathanh@nvidia.com>
Reported-by: kbuild test robot <lkp@intel.com>
Fixes: 24f73b9971 ("timers/core: Convert to hotplug state machine")
Signed-off-by: Richard Cochran <rcochran@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: John Stultz <john.stultz@linaro.org>
Cc: rt@linutronix.de
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1469610498-25914-1-git-send-email-rcochran@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-07-28 18:56:22 +02:00
Linus Torvalds
468fc7ed55 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next
Pull networking updates from David Miller:

 1) Unified UDP encapsulation offload methods for drivers, from
    Alexander Duyck.

 2) Make DSA binding more sane, from Andrew Lunn.

 3) Support QCA9888 chips in ath10k, from Anilkumar Kolli.

 4) Several workqueue usage cleanups, from Bhaktipriya Shridhar.

 5) Add XDP (eXpress Data Path), essentially running BPF programs on RX
    packets as soon as the device sees them, with the option to mirror
    the packet on TX via the same interface.  From Brenden Blanco and
    others.

 6) Allow qdisc/class stats dumps to run lockless, from Eric Dumazet.

 7) Add VLAN support to b53 and bcm_sf2, from Florian Fainelli.

 8) Simplify netlink conntrack entry layout, from Florian Westphal.

 9) Add ipv4 forwarding support to mlxsw spectrum driver, from Ido
    Schimmel, Yotam Gigi, and Jiri Pirko.

10) Add SKB array infrastructure and convert tun and macvtap over to it.
    From Michael S Tsirkin and Jason Wang.

11) Support qdisc packet injection in pktgen, from John Fastabend.

12) Add neighbour monitoring framework to TIPC, from Jon Paul Maloy.

13) Add NV congestion control support to TCP, from Lawrence Brakmo.

14) Add GSO support to SCTP, from Marcelo Ricardo Leitner.

15) Allow GRO and RPS to function on macsec devices, from Paolo Abeni.

16) Support MPLS over IPV4, from Simon Horman.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1622 commits)
  xgene: Fix build warning with ACPI disabled.
  be2net: perform temperature query in adapter regardless of its interface state
  l2tp: Correctly return -EBADF from pppol2tp_getname.
  net/mlx5_core/health: Remove deprecated create_singlethread_workqueue
  net: ipmr/ip6mr: update lastuse on entry change
  macsec: ensure rx_sa is set when validation is disabled
  tipc: dump monitor attributes
  tipc: add a function to get the bearer name
  tipc: get monitor threshold for the cluster
  tipc: make cluster size threshold for monitoring configurable
  tipc: introduce constants for tipc address validation
  net: neigh: disallow transition to NUD_STALE if lladdr is unchanged in neigh_update()
  MAINTAINERS: xgene: Add driver and documentation path
  Documentation: dtb: xgene: Add MDIO node
  dtb: xgene: Add MDIO node
  drivers: net: xgene: ethtool: Use phy_ethtool_gset and sset
  drivers: net: xgene: Use exported functions
  drivers: net: xgene: Enable MDIO driver
  drivers: net: xgene: Add backward compatibility
  drivers: net: phy: xgene: Add MDIO driver
  ...
2016-07-27 12:03:20 -07:00
Linus Torvalds
08fd8c1768 xen: features and fixes for 4.8-rc0
- ACPI support for guests on ARM platforms.
 - Generic steal time support for arm and x86.
 - Support cases where kernel cpu is not Xen VCPU number (e.g., if
   in-guest kexec is used).
 - Use the system workqueue instead of a custom workqueue in various
   places.
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Merge tag 'for-linus-4.8-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

Pull xen updates from David Vrabel:
 "Features and fixes for 4.8-rc0:

   - ACPI support for guests on ARM platforms.
   - Generic steal time support for arm and x86.
   - Support cases where kernel cpu is not Xen VCPU number (e.g., if
     in-guest kexec is used).
   - Use the system workqueue instead of a custom workqueue in various
     places"

* tag 'for-linus-4.8-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: (47 commits)
  xen: add static initialization of steal_clock op to xen_time_ops
  xen/pvhvm: run xen_vcpu_setup() for the boot CPU
  xen/evtchn: use xen_vcpu_id mapping
  xen/events: fifo: use xen_vcpu_id mapping
  xen/events: use xen_vcpu_id mapping in events_base
  x86/xen: use xen_vcpu_id mapping when pointing vcpu_info to shared_info
  x86/xen: use xen_vcpu_id mapping for HYPERVISOR_vcpu_op
  xen: introduce xen_vcpu_id mapping
  x86/acpi: store ACPI ids from MADT for future usage
  x86/xen: update cpuid.h from Xen-4.7
  xen/evtchn: add IOCTL_EVTCHN_RESTRICT
  xen-blkback: really don't leak mode property
  xen-blkback: constify instance of "struct attribute_group"
  xen-blkfront: prefer xenbus_scanf() over xenbus_gather()
  xen-blkback: prefer xenbus_scanf() over xenbus_gather()
  xen: support runqueue steal time on xen
  arm/xen: add support for vm_assist hypercall
  xen: update xen headers
  xen-pciback: drop superfluous variables
  xen-pciback: short-circuit read path used for merging write values
  ...
2016-07-27 11:35:37 -07:00
Oleg Nesterov
ce4f06dcbb stop_machine: Touch_nmi_watchdog() after MULTI_STOP_PREPARE
Suppose that stop_machine(fn) hangs because fn() hangs. In this case NMI
hard-lockup can be triggered on another CPU which does nothing wrong and
the trace from nmi_panic() won't help to investigate the problem.

And this change "fixes" the problem we (seem to) hit in practice.

 - stop_two_cpus(0, 1) races with show_state_filter() running on CPU_0.

 - CPU_1 already spins in MULTI_STOP_PREPARE state, it detects the soft
   lockup and tries to report the problem.

 - show_state_filter() enables preemption, CPU_0 calls multi_cpu_stop()
   which goes to MULTI_STOP_DISABLE_IRQ state and disables interrupts.

 - CPU_1 spends more than 10 seconds trying to flush the log buffer to
   the slow serial console.

 - NMI interrupt on CPU_0 (which now waits for CPU_1) calls nmi_panic().

Reported-by: Wang Shu <shuwang@redhat.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dave Anderson <anderson@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tejun Heo <tj@kernel.org>
Link: http://lkml.kernel.org/r/20160726185736.GB4088@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-07-27 11:12:11 +02:00
Ben Hutchings
bca014caaa module: Invalidate signatures on force-loaded modules
Signing a module should only make it trusted by the specific kernel it
was built for, not anything else.  Loading a signed module meant for a
kernel with a different ABI could have interesting effects.
Therefore, treat all signatures as invalid when a module is
force-loaded.

Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Cc: stable@vger.kernel.org
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2016-07-27 12:38:00 +09:30
Libor Pechacek
3205c36cf7 module: Issue warnings when tainting kernel
While most of the locations where a kernel taint bit is set are accompanied
with a warning message, there are two which set their bits silently.  If
the tainting module gets unloaded later on, it is almost impossible to tell
what was the reason for setting the flag.

Signed-off-by: Libor Pechacek <lpechacek@suse.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2016-07-27 12:38:00 +09:30
Rusty Russell
c75b590d60 module: fix redundant test.
[linux-4.5-rc4/kernel/module.c:1692]: (style) Redundant condition: attr.test.
'!attr.test || (attr.test && attr.test(mod))' is equivalent to '!attr.test ||
attr.test(mod)'

This code was added like this ten years ago, in c988d2b284
"modules: add version and srcversion to sysfs".

Reported-by: David Binderman <dcb314@hotmail.com>
Cc: Matt Domsch <Matt_Domsch@dell.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2016-07-27 12:38:00 +09:30
Jiri Kosina
bf262dcec6 module: fix noreturn attribute for __module_put_and_exit()
__module_put_and_exit() is makred noreturn in module.h declaration, but is
lacking the attribute in the definition, which makes some tools (such as
sparse) unhappy. Amend the definition with the attribute as well (and
reformat the declaration so that it uses more common format).

Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2016-07-27 12:38:00 +09:30
Linus Torvalds
0e06f5c0de Merge branch 'akpm' (patches from Andrew)
Merge updates from Andrew Morton:

 - a few misc bits

 - ocfs2

 - most(?) of MM

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (125 commits)
  thp: fix comments of __pmd_trans_huge_lock()
  cgroup: remove unnecessary 0 check from css_from_id()
  cgroup: fix idr leak for the first cgroup root
  mm: memcontrol: fix documentation for compound parameter
  mm: memcontrol: remove BUG_ON in uncharge_list
  mm: fix build warnings in <linux/compaction.h>
  mm, thp: convert from optimistic swapin collapsing to conservative
  mm, thp: fix comment inconsistency for swapin readahead functions
  thp: update Documentation/{vm/transhuge,filesystems/proc}.txt
  shmem: split huge pages beyond i_size under memory pressure
  thp: introduce CONFIG_TRANSPARENT_HUGE_PAGECACHE
  khugepaged: add support of collapse for tmpfs/shmem pages
  shmem: make shmem_inode_info::lock irq-safe
  khugepaged: move up_read(mmap_sem) out of khugepaged_alloc_page()
  thp: extract khugepaged from mm/huge_memory.c
  shmem, thp: respect MADV_{NO,}HUGEPAGE for file mappings
  shmem: add huge pages support
  shmem: get_unmapped_area align huge page
  shmem: prepare huge= mount option and sysfs knob
  mm, rmap: account shmem thp pages
  ...
2016-07-26 19:55:54 -07:00
Linus Torvalds
6453dbdda3 Power management material for v4.8-rc1
- Rework the cpufreq governor interface to make it more straightforward
    and modify the conservative governor to avoid using transition
    notifications (Rafael Wysocki).
 
  - Rework the handling of frequency tables by the cpufreq core to make
    it more efficient (Viresh Kumar).
 
  - Modify the schedutil governor to reduce the number of wakeups it
    causes to occur in cases when the CPU frequency doesn't need to be
    changed (Steve Muckle, Viresh Kumar).
 
  - Fix some minor issues and clean up code in the cpufreq core and
    governors (Rafael Wysocki, Viresh Kumar).
 
  - Add Intel Broxton support to the intel_pstate driver (Srinivas
    Pandruvada).
 
  - Fix problems related to the config TDP feature and to the validity
    of the MSR_HWP_INTERRUPT register in intel_pstate (Jan Kiszka,
    Srinivas Pandruvada).
 
  - Make intel_pstate update the cpu_frequency tracepoint even if
    the frequency doesn't change to avoid confusing powertop (Rafael
    Wysocki).
 
  - Clean up the usage of __init/__initdata in intel_pstate, mark some
    of its internal variables as __read_mostly and drop an unused
    structure element from it (Jisheng Zhang, Carsten Emde).
 
  - Clean up the usage of some duplicate MSR symbols in intel_pstate
    and turbostat (Srinivas Pandruvada).
 
  - Update/fix the powernv, s3c24xx and mvebu cpufreq drivers (Akshay
    Adiga, Viresh Kumar, Ben Dooks).
 
  - Fix a regression (introduced during the 4.5 cycle) in the
    pcc-cpufreq driver by reverting the problematic commit (Andreas
    Herrmann).
 
  - Add support for Intel Denverton to intel_idle, clean up Broxton
    support in it and make it explicitly non-modular (Jacob Pan,
    Jan Beulich, Paul Gortmaker).
 
  - Add support for Denverton and Ivy Bridge server to the Intel RAPL
    power capping driver and make it more careful about the handing
    of MSRs that may not be present (Jacob Pan, Xiaolong Wang).
 
  - Fix resume from hibernation on x86-64 by making the CPU offline
    during resume avoid using MONITOR/MWAIT in the "play dead" loop
    which may lead to an inadvertent "revival" of a "dead" CPU and
    a page fault leading to a kernel crash from it (Rafael Wysocki).
 
  - Make memory management during resume from hibernation more
    straightforward (Rafael Wysocki).
 
  - Add debug features that should help to detect problems related
    to hibernation and resume from it (Rafael Wysocki, Chen Yu).
 
  - Clean up hibernation core somewhat (Rafael Wysocki).
 
  - Prevent KASAN from instrumenting the hibernation core which leads
    to large numbers of false-positives from it (James Morse).
 
  - Prevent PM (hibernate and suspend) notifiers from being called
    during the cleanup phase if they have not been called during the
    corresponding preparation phase which is possible if one of the
    other notifiers returns an error at that time (Lianwei Wang).
 
  - Improve suspend-related debug printout in the tasks freezer and
    clean up suspend-related console handling (Roger Lu, Borislav
    Petkov).
 
  - Update the AnalyzeSuspend script in the kernel sources to
    version 4.2 (Todd Brandt).
 
  - Modify the generic power domains framework to make it handle
    system suspend/resume better (Ulf Hansson).
 
  - Make the runtime PM framework avoid resuming devices synchronously
    when user space changes the runtime PM settings for them and
    improve its error reporting (Rafael Wysocki, Linus Walleij).
 
  - Fix error paths in devfreq drivers (exynos, exynos-ppmu, exynos-bus)
    and in the core, make some devfreq code explicitly non-modular and
    change some of it into tristate (Bartlomiej Zolnierkiewicz,
    Peter Chen, Paul Gortmaker).
 
  - Add DT support to the generic PM clocks management code and make
    it export some more symbols (Jon Hunter, Paul Gortmaker).
 
  - Make the PCI PM core code slightly more robust against possible
    driver errors (Andy Shevchenko).
 
  - Make it possible to change DESTDIR and PREFIX in turbostat
    (Andy Shevchenko).
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Merge tag 'pm-4.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull power management updates from Rafael  Wysocki:
 "Again, the majority of changes go into the cpufreq subsystem, but
  there are no big features this time.  The cpufreq changes that stand
  out somewhat are the governor interface rework and improvements
  related to the handling of frequency tables.  Apart from those, there
  are fixes and new device/CPU IDs in drivers, cleanups and an
  improvement of the new schedutil governor.

  Next, there are some changes in the hibernation core, including a fix
  for a nasty problem related to the MONITOR/MWAIT usage by CPU offline
  during resume from hibernation, a few core improvements related to
  memory management during resume, a couple of additional debug features
  and cleanups.

  Finally, we have some fixes and cleanups in the devfreq subsystem,
  generic power domains framework improvements related to system
  suspend/resume, support for some new chips in intel_idle and in the
  power capping RAPL driver, a new version of the AnalyzeSuspend utility
  and some assorted fixes and cleanups.

  Specifics:

   - Rework the cpufreq governor interface to make it more
     straightforward and modify the conservative governor to avoid using
     transition notifications (Rafael Wysocki).

   - Rework the handling of frequency tables by the cpufreq core to make
     it more efficient (Viresh Kumar).

   - Modify the schedutil governor to reduce the number of wakeups it
     causes to occur in cases when the CPU frequency doesn't need to be
     changed (Steve Muckle, Viresh Kumar).

   - Fix some minor issues and clean up code in the cpufreq core and
     governors (Rafael Wysocki, Viresh Kumar).

   - Add Intel Broxton support to the intel_pstate driver (Srinivas
     Pandruvada).

   - Fix problems related to the config TDP feature and to the validity
     of the MSR_HWP_INTERRUPT register in intel_pstate (Jan Kiszka,
     Srinivas Pandruvada).

   - Make intel_pstate update the cpu_frequency tracepoint even if the
     frequency doesn't change to avoid confusing powertop (Rafael
     Wysocki).

   - Clean up the usage of __init/__initdata in intel_pstate, mark some
     of its internal variables as __read_mostly and drop an unused
     structure element from it (Jisheng Zhang, Carsten Emde).

   - Clean up the usage of some duplicate MSR symbols in intel_pstate
     and turbostat (Srinivas Pandruvada).

   - Update/fix the powernv, s3c24xx and mvebu cpufreq drivers (Akshay
     Adiga, Viresh Kumar, Ben Dooks).

   - Fix a regression (introduced during the 4.5 cycle) in the
     pcc-cpufreq driver by reverting the problematic commit (Andreas
     Herrmann).

   - Add support for Intel Denverton to intel_idle, clean up Broxton
     support in it and make it explicitly non-modular (Jacob Pan, Jan
     Beulich, Paul Gortmaker).

   - Add support for Denverton and Ivy Bridge server to the Intel RAPL
     power capping driver and make it more careful about the handing of
     MSRs that may not be present (Jacob Pan, Xiaolong Wang).

   - Fix resume from hibernation on x86-64 by making the CPU offline
     during resume avoid using MONITOR/MWAIT in the "play dead" loop
     which may lead to an inadvertent "revival" of a "dead" CPU and a
     page fault leading to a kernel crash from it (Rafael Wysocki).

   - Make memory management during resume from hibernation more
     straightforward (Rafael Wysocki).

   - Add debug features that should help to detect problems related to
     hibernation and resume from it (Rafael Wysocki, Chen Yu).

   - Clean up hibernation core somewhat (Rafael Wysocki).

   - Prevent KASAN from instrumenting the hibernation core which leads
     to large numbers of false-positives from it (James Morse).

   - Prevent PM (hibernate and suspend) notifiers from being called
     during the cleanup phase if they have not been called during the
     corresponding preparation phase which is possible if one of the
     other notifiers returns an error at that time (Lianwei Wang).

   - Improve suspend-related debug printout in the tasks freezer and
     clean up suspend-related console handling (Roger Lu, Borislav
     Petkov).

   - Update the AnalyzeSuspend script in the kernel sources to version
     4.2 (Todd Brandt).

   - Modify the generic power domains framework to make it handle system
     suspend/resume better (Ulf Hansson).

   - Make the runtime PM framework avoid resuming devices synchronously
     when user space changes the runtime PM settings for them and
     improve its error reporting (Rafael Wysocki, Linus Walleij).

   - Fix error paths in devfreq drivers (exynos, exynos-ppmu,
     exynos-bus) and in the core, make some devfreq code explicitly
     non-modular and change some of it into tristate (Bartlomiej
     Zolnierkiewicz, Peter Chen, Paul Gortmaker).

   - Add DT support to the generic PM clocks management code and make it
     export some more symbols (Jon Hunter, Paul Gortmaker).

   - Make the PCI PM core code slightly more robust against possible
     driver errors (Andy Shevchenko).

   - Make it possible to change DESTDIR and PREFIX in turbostat (Andy
     Shevchenko)"

* tag 'pm-4.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (89 commits)
  Revert "cpufreq: pcc-cpufreq: update default value of cpuinfo_transition_latency"
  PM / hibernate: Introduce test_resume mode for hibernation
  cpufreq: export cpufreq_driver_resolve_freq()
  cpufreq: Disallow ->resolve_freq() for drivers providing ->target_index()
  PCI / PM: check all fields in pci_set_platform_pm()
  cpufreq: acpi-cpufreq: use cached frequency mapping when possible
  cpufreq: schedutil: map raw required frequency to driver frequency
  cpufreq: add cpufreq_driver_resolve_freq()
  cpufreq: intel_pstate: Check cpuid for MSR_HWP_INTERRUPT
  intel_pstate: Update cpu_frequency tracepoint every time
  cpufreq: intel_pstate: clean remnant struct element
  PM / tools: scripts: AnalyzeSuspend v4.2
  x86 / hibernate: Use hlt_play_dead() when resuming from hibernation
  cpufreq: powernv: Replacing pstate_id with frequency table index
  intel_pstate: Fix MSR_CONFIG_TDP_x addressing in core_get_max_pstate()
  PM / hibernate: Image data protection during restoration
  PM / hibernate: Add missing braces in __register_nosave_region()
  PM / hibernate: Clean up comments in snapshot.c
  PM / hibernate: Clean up function headers in snapshot.c
  PM / hibernate: Add missing braces in hibernate_setup()
  ...
2016-07-26 17:29:07 -07:00
Johannes Weiner
cb773df88a cgroup: remove unnecessary 0 check from css_from_id()
css_idr allocation starts at 1, so index 0 will never point to an item.
css_from_id() currently filters that before asking idr_find(), but
idr_find() would also just return NULL, so this is not needed.

Link: http://lkml.kernel.org/r/20160617162427.GC19084@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vladimir Davydov <vdavydov@virtuozzo.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Nikolay Borisov <kernel@kyup.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-07-26 16:19:19 -07:00
Johannes Weiner
1fe4d021ac cgroup: fix idr leak for the first cgroup root
The valid cgroup hierarchy ID range includes 0, so we can't filter for
positive numbers when freeing it, or it'll leak the first ID.  No big
deal, just disruptive when reading the code.

The ID is freed during error handling and when the reference count hits
zero, so the double-free test is not necessary; remove it.

Link: http://lkml.kernel.org/r/20160617162359.GB19084@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vladimir Davydov <vdavydov@virtuozzo.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Nikolay Borisov <kernel@kyup.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-07-26 16:19:19 -07:00