Currently the adjusments made as part of perf_event_task_tick() use the
percpu rotation lists to iterate over any active PMU contexts, but these
are not used by the context rotation code, having been replaced by
separate (per-context) hrtimer callbacks. However, some manipulation of
the rotation lists (i.e. removal of contexts) has remained in
perf_rotate_context(). This leads to the following issues:
* Contexts are not always removed from the rotation lists. Removal of
PMUs which have been placed in rotation lists, but have not been
removed by a hrtimer callback can result in corruption of the rotation
lists (when memory backing the context is freed).
This has been observed to result in hangs when PMU drivers built as
modules are inserted and removed around the creation of events for
said PMUs.
* Contexts which do not require rotation may be removed from the
rotation lists as a result of a hrtimer, and will not be considered by
the unthrottling code in perf_event_task_tick.
This patch fixes the issue by updating the rotation ist when events are
scheduled in/out, ensuring that each rotation list stays in sync with
the HW state. As each event holds a refcount on the module of its PMU,
this ensures that when a PMU module is unloaded none of its CPU contexts
can be in a rotation list. By maintaining a list of perf_event_contexts
rather than perf_event_cpu_contexts, we don't need separate paths to
handle the cpu and task contexts, which also makes the code a little
simpler.
As the rotation_list variables are not used for rotation, these are
renamed to active_ctx_list, which better matches their current function.
perf_pmu_rotate_{start,stop} are renamed to
perf_pmu_ctx_{activate,deactivate}.
Reported-by: Johannes Jensen <johannes.jensen@arm.com>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Will Deacon <Will.Deacon@arm.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20150129134511.GR17721@leverpostej
Signed-off-by: Ingo Molnar <mingo@kernel.org>
When initialising an event, perf_init_event will call try_module_get() to
ensure that the PMU's module cannot be removed for the lifetime of the
event, with __free_event() dropping the reference when the event is
finally destroyed. If something fails after the event has been
initialised, but before the event is installed, perf_event_alloc will
drop the reference on the module.
However, if we fail to initialise an event for some reason (e.g. we ask
an uncore PMU to perform sampling, and it refuses to initialise the
event), we do not drop the refcount. If we try to open such a bogus
event without a precise IDR type, we will loop over each PMU in the pmus
list, incrementing each of their refcounts without decrementing them.
This patch adds a module_put when pmu->event_init(event) fails, ensuring
that the refcounts are balanced in failure cases. As the innards of the
precise and search based initialisation look very similar, this logic is
hoisted out into a new helper function. While the early return for the
failed try_module_get is removed from the search case, this is handled
by the remaining return when ret is not -ENOENT.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1420642611-22667-1-git-send-email-mark.rutland@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Currently we flag available data (via poll syscall) on perf fd with
POLL_IN macro, which is normally used for SIGIO interface.
We've been lucky, because POLLIN (0x1) is subset of POLL_IN (0x20001)
and sys_poll (do_pollfd function) cut the extra bit out (0x20000).
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1422467678-22341-1-git-send-email-jolsa@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
So what I suspect; but I'm in zombie mode today it seems; is that while
I initially thought that it was impossible for ctx to change when
refcount dropped to 0, I now suspect its possible.
Note that until perf_remove_from_context() the event is still active and
visible on the lists. So a concurrent sys_perf_event_open() from another
task into this task can race.
Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Stephane Eranian <eranian@gmail.com>
Cc: mark.rutland@arm.com
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20150129134434.GB26304@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Jiri reported triggering the new WARN_ON_ONCE in event_sched_out over
the weekend:
event_sched_out.isra.79+0x2b9/0x2d0
group_sched_out+0x69/0xc0
ctx_sched_out+0x106/0x130
task_ctx_sched_out+0x37/0x70
__perf_install_in_context+0x70/0x1a0
remote_function+0x48/0x60
generic_exec_single+0x15b/0x1d0
smp_call_function_single+0x67/0xa0
task_function_call+0x53/0x80
perf_install_in_context+0x8b/0x110
I think the below should cure this; if we install a group leader it
will iterate the (still intact) group list and find its siblings and
try and install those too -- even though those still have the old
event->ctx -- in the new ctx.
Upon installing the first group sibling we'd try and schedule out the
group and trigger the above warn.
Fix this by installing the group leader last, installing siblings
would have no effect, they're not reachable through the group lists
and therefore we don't schedule them.
Also delay resetting the state until we're absolutely sure the events
are quiescent.
Reported-by: Jiri Olsa <jolsa@redhat.com>
Reported-by: vincent.weaver@maine.edu
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20150126162639.GA21418@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
There have been a few reported issues wrt. the lack of locking around
changing event->ctx. This patch tries to address those.
It avoids the whole rwsem thing; and while it appears to work, please
give it some thought in review.
What I did fail at is sensible runtime checks on the use of
event->ctx, the RCU use makes it very hard.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20150123125834.209535886@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Add a few WARN()s to catch things that should never happen.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20150123125834.150481799@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Commit 8eb23b9f35 ("sched: Debug nested sleeps") added code to report
on nested sleep conditions, which we generally want to avoid because the
inner sleeping operation can re-set the thread state to TASK_RUNNING,
but that will then cause the outer sleep loop not actually sleep when it
calls schedule.
However, that's actually valid traditional behavior, with the inner
sleep being some fairly rare case (like taking a sleeping lock that
normally doesn't actually need to sleep).
And the debug code would actually change the state of the task to
TASK_RUNNING internally, which makes that kind of traditional and
working code not work at all, because now the nested sleep doesn't just
sometimes cause the outer one to not block, but will cause it to happen
every time.
In particular, it will cause the cardbus kernel daemon (pccardd) to
basically busy-loop doing scheduling, converting a laptop into a heater,
as reported by Bruno Prémont. But there may be other legacy uses of
that nested sleep model in other drivers that are also likely to never
get converted to the new model.
This fixes both cases:
- don't set TASK_RUNNING when the nested condition happens (note: even
if WARN_ONCE() only _warns_ once, the return value isn't whether the
warning happened, but whether the condition for the warning was true.
So despite the warning only happening once, the "if (WARN_ON(..))"
would trigger for every nested sleep.
- in the cases where we knowingly disable the warning by using
"sched_annotate_sleep()", don't change the task state (that is used
for all core scheduling decisions), instead use '->task_state_change'
that is used for the debugging decision itself.
(Credit for the second part of the fix goes to Oleg Nesterov: "Can't we
avoid this subtle change in behaviour DEBUG_ATOMIC_SLEEP adds?" with the
suggested change to use 'task_state_change' as part of the test)
Reported-and-bisected-by: Bruno Prémont <bonbons@linux-vserver.org>
Tested-by: Rafael J Wysocki <rjw@rjwysocki.net>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Cc: Ilya Dryomov <ilya.dryomov@inktank.com>,
Cc: Mike Galbraith <umgwanakikbuti@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Hurley <peter@hurleysoftware.com>,
Cc: Davidlohr Bueso <dave@stgolabs.net>,
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull perf fixes from Ingo Molnar:
"Mostly tooling fixes, but also an event groups fix, two PMU driver
fixes and a CPU model variant addition"
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf: Tighten (and fix) the grouping condition
perf/x86/intel: Add model number for Airmont
perf/rapl: Fix crash in rapl_scale()
perf/x86/intel/uncore: Move uncore_box_init() out of driver initialization
perf probe: Fix probing kretprobes
perf symbols: Introduce 'for' method to iterate over the symbols with a given name
perf probe: Do not rely on map__load() filter to find symbols
perf symbols: Introduce method to iterate symbols ordered by name
perf symbols: Return the first entry with a given name in find_by_name method
perf annotate: Fix memory leaks in LOCK handling
perf annotate: Handle ins parsing failures
perf scripting perl: Force to use stdbool
perf evlist: Remove extraneous 'was' on error message
The fix from 9fc81d8742 ("perf: Fix events installation during
moving group") was incomplete in that it failed to recognise that
creating a group with events for different CPUs is semantically
broken -- they cannot be co-scheduled.
Furthermore, it leads to real breakage where, when we create an event
for CPU Y and then migrate it to form a group on CPU X, the code gets
confused where the counter is programmed -- triggered in practice
as well by me via the perf fuzzer.
Fix this by tightening the rules for creating groups. Only allow
grouping of counters that can be co-scheduled in the same context.
This means for the same task and/or the same cpu.
Fixes: 9fc81d8742 ("perf: Fix events installation during moving group")
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20150123125834.090683288@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull networking fixes from David Miller:
1) Don't OOPS on socket AIO, from Christoph Hellwig.
2) Scheduled scans should be aborted upon RFKILL, from Emmanuel
Grumbach.
3) Fix sleep in atomic context in kvaser_usb, from Ahmed S Darwish.
4) Fix RCU locking across copy_to_user() in bpf code, from Alexei
Starovoitov.
5) Lots of crash, memory leak, short TX packet et al bug fixes in
sh_eth from Ben Hutchings.
6) Fix memory corruption in SCTP wrt. INIT collitions, from Daniel
Borkmann.
7) Fix return value logic for poll handlers in netxen, enic, and bnx2x.
From Eric Dumazet and Govindarajulu Varadarajan.
8) Header length calculation fix in mac80211 from Fred Chou.
9) mv643xx_eth doesn't handle highmem correctly in non-TSO code paths.
From Ezequiel Garcia.
10) udp_diag has bogus logic in it's hash chain skipping, copy same fix
tcp diag used. From Herbert Xu.
11) amd-xgbe programs wrong rx flow control register, from Thomas
Lendacky.
12) Fix race leading to use after free in ping receive path, from Subash
Abhinov Kasiviswanathan.
13) Cache redirect routes otherwise we can get a heavy backlog of rcu
jobs liberating DST_NOCACHE entries. From Hannes Frederic Sowa.
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (48 commits)
net: don't OOPS on socket aio
stmmac: prevent probe drivers to crash kernel
bnx2x: fix napi poll return value for repoll
ipv6: replacing a rt6_info needs to purge possible propagated rt6_infos too
sh_eth: Fix DMA-API usage for RX buffers
sh_eth: Check for DMA mapping errors on transmit
sh_eth: Ensure DMA engines are stopped before freeing buffers
sh_eth: Remove RX overflow log messages
ping: Fix race in free in receive path
udp_diag: Fix socket skipping within chain
can: kvaser_usb: Fix state handling upon BUS_ERROR events
can: kvaser_usb: Retry the first bulk transfer on -ETIMEDOUT
can: kvaser_usb: Send correct context to URB completion
can: kvaser_usb: Do not sleep in atomic context
ipv4: try to cache dst_entries which would cause a redirect
samples: bpf: relax test_maps check
bpf: rcu lock must not be held when calling copy_to_user()
net: sctp: fix slab corruption from use after free on INIT collisions
net: mv643xx_eth: Fix highmem support in non-TSO egress path
sh_eth: Fix serialisation of interrupt disable with interrupt & NAPI handlers
...
BUG: sleeping function called from invalid context at mm/memory.c:3732
in_atomic(): 0, irqs_disabled(): 0, pid: 671, name: test_maps
1 lock held by test_maps/671:
#0: (rcu_read_lock){......}, at: [<0000000000264190>] map_lookup_elem+0xe8/0x260
Call Trace:
([<0000000000115b7e>] show_trace+0x12e/0x150)
[<0000000000115c40>] show_stack+0xa0/0x100
[<00000000009b163c>] dump_stack+0x74/0xc8
[<000000000017424a>] ___might_sleep+0x23a/0x248
[<00000000002b58e8>] might_fault+0x70/0xe8
[<0000000000264230>] map_lookup_elem+0x188/0x260
[<0000000000264716>] SyS_bpf+0x20e/0x840
Fix it by allocating temporary buffer to store map element value.
Fixes: db20fd2b01 ("bpf: add lookup/update/delete/iterate methods to BPF maps")
Reported-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Acked-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Pull cgroup fix from Tejun Heo:
"The lifetime rules of cgroup hierarchies always have been somewhat
counter-intuitive and cgroup core tried to enforce that hierarchies
w/o userland-visible usages must die in finite amount of time so that
the controllers can be reused for other hierarchies; unfortunately,
this can't be implemented reasonably for the memory controller - the
kmemcg part doesn't have any way to forcefully drain the existing
usages, leading to an interruptible hang if a following mount attempts
to use the controller in any way.
So, it seems like we're stuck with "hierarchies live on till they die
whenever that may be" at least for now. This pretty much confines
attaching controllers to hierarchies to before the hierarchies are
actively used by making dynamic configurations post active usages
unreliable. This has never been reliable and should be fine in
practice given how cgroups are used.
After the patch, hierarchies aren't killed if it isn't already
drained. A following mount attempt of the same mount options will
reuse the existing hierarchy. Mount attempts with differing options
will fail w/ -EBUSY"
* 'for-3.19-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
cgroup: prevent mount hang due to memory controller lifetime
Pull x86 fixes from Thomas Gleixner:
"Hopefully the last round of fixes for 3.19
- regression fix for the LDT changes
- regression fix for XEN interrupt handling caused by the APIC
changes
- regression fixes for the PAT changes
- last minute fixes for new the MPX support
- regression fix for 32bit UP
- fix for a long standing relocation issue on 64bit tagged for stable
- functional fix for the Hyper-V clocksource tagged for stable
- downgrade of a pr_err which tends to confuse users
Looks a bit on the large side, but almost half of it are valuable
comments"
* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/tsc: Change Fast TSC calibration failed from error to info
x86/apic: Re-enable PCI_MSI support for non-SMP X86_32
x86, mm: Change cachemode exports to non-gpl
x86, tls: Interpret an all-zero struct user_desc as "no segment"
x86, tls, ldt: Stop checking lm in LDT_empty
x86, mpx: Strictly enforce empty prctl() args
x86, mpx: Fix potential performance issue on unmaps
x86, mpx: Explicitly disable 32-bit MPX support on 64-bit kernels
x86, hyperv: Mark the Hyper-V clocksource as being continuous
x86: Don't rely on VMWare emulating PAT MSR correctly
x86, irq: Properly tag virtualization entry in /proc/interrupts
x86, boot: Skip relocs when load address unchanged
x86/xen: Override ACPI IRQ management callback __acpi_unregister_gsi
ACPI: pci: Do not clear pci_dev->irq in acpi_pci_irq_disable()
x86/xen: Treat SCI interrupt as normal GSI interrupt
Pull timer fixes from Thomas Gleixner:
"A set of small fixes:
- regression fix for exynos_mct clocksource
- trivial build fix for kona clocksource
- functional one liner fix for the sh_tmu clocksource
- two validation fixes to prevent (root only) data corruption in the
kernel via settimeofday and adjtimex. Tagged for stable"
* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
time: adjtimex: Validate the ADJ_FREQUENCY values
time: settimeofday: Validate the values of tv from user
clocksource: sh_tmu: Set cpu_possible_mask to fix SMP broadcast
clocksource: kona: fix __iomem annotation
clocksource: exynos_mct: Fix bitmask regression for exynos4_mct_write
Description from Michael Kerrisk. He suggested an identical patch
to one I had already coded up and tested.
commit fe3d197f84 "x86, mpx: On-demand kernel allocation of bounds
tables" added two new prctl() operations, PR_MPX_ENABLE_MANAGEMENT and
PR_MPX_DISABLE_MANAGEMENT. However, no checks were included to ensure
that unused arguments are zero, as is done in many existing prctl()s
and as should be done for all new prctl()s. This patch adds the
required checks.
Suggested-by: Andy Lutomirski <luto@amacapital.net>
Suggested-by: Michael Kerrisk <mtk.manpages@gmail.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dave Hansen <dave@sr71.net>
Link: http://lkml.kernel.org/r/20150108223022.7F56FD13@viggo.jf.intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
First two are minor fallout from the param rework which went in this merge
window.
Next three are a series which fixes a longstanding (but never previously
reported and unlikely , so no CC stable) race between kallsyms and freeing
the init section.
Finally, a minor cleanup as our module refcount will now be -1 during
unload.
Thanks,
Rusty.
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Merge tag 'fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux
Pull module and param fixes from Rusty Russell:
"Surprising number of fixes this merge window :(
The first two are minor fallout from the param rework which went in
this merge window.
The next three are a series which fixes a longstanding (but never
previously reported and unlikely , so no CC stable) race between
kallsyms and freeing the init section.
Finally, a minor cleanup as our module refcount will now be -1 during
unload"
* tag 'fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux:
module: make module_refcount() a signed integer.
module: fix race in kallsyms resolution during module load success.
module: remove mod arg from module_free, rename module_memfree().
module_arch_freeing_init(): new hook for archs before module->module_init freed.
param: fix uninitialized read with CONFIG_DEBUG_LOCK_ALLOC
param: initialize store function to NULL if not available.
Since b2052564e6 ("mm: memcontrol: continue cache reclaim from
offlined groups"), re-mounting the memory controller after using it is
very likely to hang.
The cgroup core assumes that any remaining references after deleting a
cgroup are temporary in nature, and synchroneously waits for them, but
the above-mentioned commit has left-over page cache pin its css until
it is reclaimed naturally. That being said, swap entries and charged
kernel memory have been doing the same indefinite pinning forever, the
bug is just more likely to trigger with left-over page cache.
Reparenting kernel memory is highly impractical, which leaves changing
the cgroup assumptions to reflect this: once a controller has been
mounted and used, it has internal state that is independent from mount
and cgroup lifetime. It can be unmounted and remounted, but it can't
be reconfigured during subsequent mounts.
Don't offline the controller root as long as there are any children,
dead or alive. A remount will no longer wait for these old references
to drain, it will simply mount the persistent controller state again.
Reported-by: "Suzuki K. Poulose" <Suzuki.Poulose@arm.com>
Reported-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
James Bottomley points out that it will be -1 during unload. It's
only used for diagnostics, so let's not hide that as it could be a
clue as to what's gone wrong.
Cc: Jason Wessel <jason.wessel@windriver.com>
Acked-and-documention-added-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Reviewed-by: Masami Hiramatsu <maasami.hiramatsu.pt@hitachi.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Pull workqueue fix from Tejun Heo:
"The xfs folks have been running into weird and very rare lockups for
some time now. I didn't think this could have been from workqueue
side because no one else was reporting it. This time, Eric had a
kdump which we looked into and it turned out this actually was a
workqueue bug and the bug has been there since the beginning of
concurrency managed workqueue.
A worker pool ensures forward progress of the workqueues associated
with it by always having at least one worker reserved from executing
work items. When the pool is under contention, the idle one tries to
create more workers for the pool and if that doesn't succeed quickly
enough, it calls the rescuers to the pool.
This logic had a subtle race condition in an early exit path. When a
worker invokes this manager function, the function may return %false
indicating that the caller may proceed to executing work items either
because another worker is already performing the role or conditions
have changed and the pool is no longer under contention.
The latter part depended on the assumption that whether more workers
are necessary or not remains stable while the pool is locked; however,
pool->nr_running (concurrency count) may change asynchronously and it
getting bumped from zero asynchronously could send off the last idle
worker to execute work items.
The race window is fairly narrow, and, even when it gets triggered,
the pool deadlocks iff if all work items get blocked on pending work
items of the pool, which is highly unlikely but can be triggered by
xfs.
The patch removes the race window by removing the early exit path,
which doesn't server any purpose anymore anyway"
* 'for-3.19-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
workqueue: fix subtle pool management issue which can stall whole worker_pool
The kallsyms routines (module_symbol_name, lookup_module_* etc) disable
preemption to walk the modules rather than taking the module_mutex:
this is because they are used for symbol resolution during oopses.
This works because there are synchronize_sched() and synchronize_rcu()
in the unload and failure paths. However, there's one case which doesn't
have that: the normal case where module loading succeeds, and we free
the init section.
We don't want a synchronize_rcu() there, because it would slow down
module loading: this bug was introduced in 2009 to speed module
loading in the first place.
Thus, we want to do the free in an RCU callback. We do this in the
simplest possible way by allocating a new rcu_head: if we put it in
the module structure we'd have to worry about that getting freed.
Reported-by: Rui Xiang <rui.xiang@huawei.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Nothing needs the module pointer any more, and the next patch will
call it from RCU, where the module itself might no longer exist.
Removing the arg is the safest approach.
This just codifies the use of the module_alloc/module_free pattern
which ftrace and bpf use.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Cc: Mikael Starvik <starvik@axis.com>
Cc: Jesper Nilsson <jesper.nilsson@axis.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Ley Foon Tan <lftan@altera.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: x86@kernel.org
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: linux-cris-kernel@axis.com
Cc: linux-kernel@vger.kernel.org
Cc: linux-mips@linux-mips.org
Cc: nios2-dev@lists.rocketboards.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: sparclinux@vger.kernel.org
Cc: netdev@vger.kernel.org
Archs have been abusing module_free() to clean up their arch-specific
allocations. Since module_free() is also (ab)used by BPF and trace code,
let's keep it to simple allocations, and provide a hook called before
that.
This means that avr32, ia64, parisc and s390 no longer need to implement
their own module_free() at all. avr32 doesn't need module_finalize()
either.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Haavard Skinnemoen <hskinnemoen@gmail.com>
Cc: Hans-Christian Egtvedt <egtvedt@samfundet.no>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Helge Deller <deller@gmx.de>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: linux-kernel@vger.kernel.org
Cc: linux-ia64@vger.kernel.org
Cc: linux-parisc@vger.kernel.org
Cc: linux-s390@vger.kernel.org
ignore_lockdep is uninitialized, and sysfs_attr_init() doesn't initialize
it, so memset to 0.
Reported-by: Huang Ying <ying.huang@intel.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Avoid overflow possibility.
[ The overflow is purely theoretical, since this is used for memory
ranges that aren't even close to using the full 64 bits, but this is
the right thing to do regardless. - Linus ]
Signed-off-by: Louis Langholtz <lou_langholtz@me.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Peter Anvin <hpa@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
A worker_pool's forward progress is guaranteed by the fact that the
last idle worker assumes the manager role to create more workers and
summon the rescuers if creating workers doesn't succeed in timely
manner before proceeding to execute work items.
This manager role is implemented in manage_workers(), which indicates
whether the worker may proceed to work item execution with its return
value. This is necessary because multiple workers may contend for the
manager role, and, if there already is a manager, others should
proceed to work item execution.
Unfortunately, the function also indicates that the worker may proceed
to work item execution if need_to_create_worker() is false at the head
of the function. need_to_create_worker() tests the following
conditions.
pending work items && !nr_running && !nr_idle
The first and third conditions are protected by pool->lock and thus
won't change while holding pool->lock; however, nr_running can change
asynchronously as other workers block and resume and while it's likely
to be zero, as someone woke this worker up in the first place, some
other workers could have become runnable inbetween making it non-zero.
If this happens, manage_worker() could return false even with zero
nr_idle making the worker, the last idle one, proceed to execute work
items. If then all workers of the pool end up blocking on a resource
which can only be released by a work item which is pending on that
pool, the whole pool can deadlock as there's no one to create more
workers or summon the rescuers.
This patch fixes the problem by removing the early exit condition from
maybe_create_worker() and making manage_workers() return false iff
there's already another manager, which ensures that the last worker
doesn't start executing work items.
We can leave the early exit condition alone and just ignore the return
value but the only reason it was put there is because the
manage_workers() used to perform both creations and destructions of
workers and thus the function may be invoked while the pool is trying
to reduce the number of workers. Now that manage_workers() is called
only when more workers are needed, the only case this early exit
condition is triggered is rare race conditions rendering it pointless.
Tested with simulated workload and modified workqueue code which
trigger the pool deadlock reliably without this patch.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Eric Sandeen <sandeen@sandeen.net>
Link: http://lkml.kernel.org/g/54B019F4.8030009@sandeen.net
Cc: Dave Chinner <david@fromorbit.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: stable@vger.kernel.org
the mixture of function graph tracing and kprobes.
When jprobes and function graph tracing is enabled at the same time
it will crash the system.
# modprobe jprobe_example
# echo function_graph > /sys/kernel/debug/tracing/current_tracer
After the first fork (jprobe_example probes it), the system will crash.
This is due to the way jprobes copies the stack frame and does not
do a normal function return. This messes up with the function graph
tracing accounting which hijacks the return address from the stack
and replaces it with a hook function. It saves the return addresses in
a separate stack to put back the correct return address when done.
But because the jprobe functions do not do a normal return, their
stack addresses are not put back until the function they probe is called,
which means that the probed function will get the return address of
the jprobe handler instead of its own.
The simple fix here was to disable function graph tracing while the
jprobe handler is being called.
While debugging this I found two minor bugs with the function graph
tracing.
The first was about the function graph tracer sharing its function hash
with the function tracer (they both get filtered by the same input).
The changing of the set_ftrace_filter would not sync the function recording
records after a change if the function tracer was disabled but the
function graph tracer was enabled. This was due to the update only checking
one of the ops instead of the shared ops to see if they were enabled and
should perform the sync. This caused the ftrace accounting to break and
a ftrace_bug() would be triggered, disabling ftrace until a reboot.
The second was that the check to update records only checked one of the
filter hashes. It needs to test both the "filter" and "notrace" hashes.
The "filter" hash determines what functions to trace where as the "notrace"
hash determines what functions not to trace (trace all but these).
Both hashes need to be passed to the update code to find out what change
is being done during the update. This also broke the ftrace record
accounting and triggered a ftrace_bug().
This patch set also include two more fixes that were reported separately
from the kprobe issue.
One was that init_ftrace_syscalls() was called twice at boot up.
This is not a major bug, but that call performed a rather large kmalloc
(NR_syscalls * sizeof(*syscalls_metadata)). The second call made the first
one a memory leak, and wastes memory.
The other fix is a regression caused by an update in the v3.19 merge window.
The moving to enable events early, moved the enabling before PID 1 was
created. The syscall events require setting the TIF_SYSCALL_TRACEPOINT
for all tasks. But for_each_process_thread() does not include the swapper
task (PID 0), and ended up being a nop. A suggested fix was to add
the init_task() to have its flag set, but I didn't really want to mess
with PID 0 for this minor bug. Instead I disable and re-enable events again
at early_initcall() where it use to be enabled. This also handles any other
event that might have its own reg function that could break at early
boot up.
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Merge tag 'trace-fixes-v3.19-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull ftrace fixes from Steven Rostedt:
"This holds a few fixes to the ftrace infrastructure as well as the
mixture of function graph tracing and kprobes.
When jprobes and function graph tracing is enabled at the same time it
will crash the system:
# modprobe jprobe_example
# echo function_graph > /sys/kernel/debug/tracing/current_tracer
After the first fork (jprobe_example probes it), the system will
crash.
This is due to the way jprobes copies the stack frame and does not do
a normal function return. This messes up with the function graph
tracing accounting which hijacks the return address from the stack and
replaces it with a hook function. It saves the return addresses in a
separate stack to put back the correct return address when done. But
because the jprobe functions do not do a normal return, their stack
addresses are not put back until the function they probe is called,
which means that the probed function will get the return address of
the jprobe handler instead of its own.
The simple fix here was to disable function graph tracing while the
jprobe handler is being called.
While debugging this I found two minor bugs with the function graph
tracing.
The first was about the function graph tracer sharing its function
hash with the function tracer (they both get filtered by the same
input). The changing of the set_ftrace_filter would not sync the
function recording records after a change if the function tracer was
disabled but the function graph tracer was enabled. This was due to
the update only checking one of the ops instead of the shared ops to
see if they were enabled and should perform the sync. This caused the
ftrace accounting to break and a ftrace_bug() would be triggered,
disabling ftrace until a reboot.
The second was that the check to update records only checked one of
the filter hashes. It needs to test both the "filter" and "notrace"
hashes. The "filter" hash determines what functions to trace where as
the "notrace" hash determines what functions not to trace (trace all
but these). Both hashes need to be passed to the update code to find
out what change is being done during the update. This also broke the
ftrace record accounting and triggered a ftrace_bug().
This patch set also include two more fixes that were reported
separately from the kprobe issue.
One was that init_ftrace_syscalls() was called twice at boot up. This
is not a major bug, but that call performed a rather large kmalloc
(NR_syscalls * sizeof(*syscalls_metadata)). The second call made the
first one a memory leak, and wastes memory.
The other fix is a regression caused by an update in the v3.19 merge
window. The moving to enable events early, moved the enabling before
PID 1 was created. The syscall events require setting the
TIF_SYSCALL_TRACEPOINT for all tasks. But for_each_process_thread()
does not include the swapper task (PID 0), and ended up being a nop.
A suggested fix was to add the init_task() to have its flag set, but I
didn't really want to mess with PID 0 for this minor bug. Instead I
disable and re-enable events again at early_initcall() where it use to
be enabled. This also handles any other event that might have its own
reg function that could break at early boot up"
* tag 'trace-fixes-v3.19-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
tracing: Fix enabling of syscall events on the command line
tracing: Remove extra call to init_ftrace_syscalls()
ftrace/jprobes/x86: Fix conflict between jprobes and function graph tracing
ftrace: Check both notrace and filter for old hash
ftrace: Fix updating of filters for shared global_ops filters
Commit 5f893b2639 "tracing: Move enabling tracepoints to just after
rcu_init()" broke the enabling of system call events from the command
line. The reason was that the enabling of command line trace events
was moved before PID 1 started, and the syscall tracepoints require
that all tasks have the TIF_SYSCALL_TRACEPOINT flag set. But the
swapper task (pid 0) is not part of that. Since the swapper task is the
only task that is running at this early in boot, no task gets the
flag set, and the tracepoint never gets reached.
Instead of setting the swapper task flag (there should be no reason to
do that), re-enabled trace events again after the init thread (PID 1)
has been started. It requires disabling all command line events and
re-enabling them, as just enabling them again will not reset the logic
to set the TIF_SYSCALL_TRACEPOINT flag, as the syscall tracepoint will
be fooled into thinking that it was already set, and wont try setting
it again. For this reason, we must first disable it and re-enable it.
Link: http://lkml.kernel.org/r/1421188517-18312-1-git-send-email-mpe@ellerman.id.au
Link: http://lkml.kernel.org/r/20150115040506.216066449@goodmis.org
Reported-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
trace_init() calls init_ftrace_syscalls() and then calls trace_event_init()
which also calls init_ftrace_syscalls(). It makes more sense to only
call it from trace_event_init().
Calling it twice wastes memory, as it allocates the syscall events twice,
and loses the first copy of it.
Link: http://lkml.kernel.org/r/54AF53BD.5070303@huawei.com
Link: http://lkml.kernel.org/r/20150115040505.930398632@goodmis.org
Reported-by: Wang Nan <wangnan0@huawei.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Using just the filter for checking for trampolines or regs is not enough
when updating the code against the records that represent all functions.
Both the filter hash and the notrace hash need to be checked.
To trigger this bug (using trace-cmd and perf):
# perf probe -a do_fork
# trace-cmd start -B foo -e probe
# trace-cmd record -p function_graph -n do_fork sleep 1
The trace-cmd record at the end clears the filter before it disables
function_graph tracing and then that causes the accounting of the
ftrace function records to become incorrect and causes ftrace to bug.
Link: http://lkml.kernel.org/r/20150114154329.358378039@goodmis.org
Cc: stable@vger.kernel.org
[ still need to switch old_hash_ops to old_ops_hash ]
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
As the set_ftrace_filter affects both the function tracer as well as the
function graph tracer, the ops that represent each have a shared
ftrace_ops_hash structure. This allows both to be updated when the filter
files are updated.
But if function graph is enabled and the global_ops (function tracing) ops
is not, then it is possible that the filter could be changed without the
update happening for the function graph ops. This will cause the changes
to not take place and may even cause a ftrace_bug to occur as it could mess
with the trampoline accounting.
The solution is to check if the ops uses the shared global_ops filter and
if the ops itself is not enabled, to check if there's another ops that is
enabled and also shares the global_ops filter. In that case, the
modification still needs to be executed.
Link: http://lkml.kernel.org/r/20150114154329.055980438@goodmis.org
Cc: stable@vger.kernel.org # 3.17+
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Both Linus (most recent) and Steve (a while ago) reported that perf
related callbacks have massive stack bloat.
The problem is that software events need a pt_regs in order to
properly report the event location and unwind stack. And because we
could not assume one was present we allocated one on stack and filled
it with minimal bits required for operation.
Now, pt_regs is quite large, so this is undesirable. Furthermore it
turns out that most sites actually have a pt_regs pointer available,
making this even more onerous, as the stack space is pointless waste.
This patch addresses the problem by observing that software events
have well defined nesting semantics, therefore we can use static
per-cpu storage instead of on-stack.
Linus made the further observation that all but the scheduler callers
of perf_sw_event() have a pt_regs available, so we change the regular
perf_sw_event() to require a valid pt_regs (where it used to be
optional) and add perf_sw_event_sched() for the scheduler.
We have a scheduler specific call instead of a more generic _noregs()
like construct because we can assume non-recursion from the scheduler
and thereby simplify the code further (_noregs would have to put the
recursion context call inline in order to assertain which __perf_regs
element to use).
One last note on the implementation of perf_trace_buf_prepare(); we
allow .regs = NULL for those cases where we already have a pt_regs
pointer available and do not need another.
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Reported-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Javi Merino <javi.merino@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Petr Mladek <pmladek@suse.cz>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tom Zanussi <tom.zanussi@linux.intel.com>
Cc: Vaibhav Nagarnaik <vnagarnaik@google.com>
Link: http://lkml.kernel.org/r/20141216115041.GW3337@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull scheduler fixes from Ingo Molnar:
"Misc fixes: group scheduling corner case fix, two deadline scheduler
fixes, effective_load() overflow fix, nested sleep fix, 6144 CPUs
system fix"
* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched/fair: Fix RCU stall upon -ENOMEM in sched_create_group()
sched/deadline: Avoid double-accounting in case of missed deadlines
sched/deadline: Fix migration of SCHED_DEADLINE tasks
sched: Fix odd values in effective_load() calculations
sched, fanotify: Deal with nested sleeps
sched: Fix KMALLOC_MAX_SIZE overflow during cpumask allocation
Pull perf fixes from Ingo Molnar:
"Mostly tooling fixes, but also some kernel side fixes: uncore PMU
driver fix, user regs sampling fix and an instruction decoder fix that
unbreaks PEBS precise sampling"
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf/x86/uncore/hsw-ep: Handle systems with only two SBOXes
perf/x86_64: Improve user regs sampling
perf: Move task_pt_regs sampling into arch code
x86: Fix off-by-one in instruction decoder
perf hists browser: Fix segfault when showing callchain
perf callchain: Free callchains when hist entries are deleted
perf hists: Fix children sort key behavior
perf diff: Fix to sort by baseline field by default
perf list: Fix --raw-dump option
perf probe: Fix crash in dwarf_getcfi_elf
perf probe: Fix to fall back to find probe point in symbols
perf callchain: Append callchains only when requested
perf ui/tui: Print backtrace symbols when segfault occurs
perf report: Show progress bar for output resorting
Pull locking fixes from Ingo Molnar:
"A liblockdep fix and a mutex_unlock() mutex-debugging fix"
* 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
mutex: Always clear owner field upon mutex_unlock()
tools/liblockdep: Fix debug_check thinko in mutex destroy
Cleanups
kdb: Remove unused command flags, repeat flags and KDB_REPEAT_NONE
Fixes
kgdb/kdb: Allow access on a single core, if a CPU round up is deemed
impossible, which will allow inspection of the now "trashed" kernel
kdb: Add enable mask for the command groups
kdb: access controls to restrict sensitive commands
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Merge tag 'for_linus-3.19-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/kgdb
Pull kgdb/kdb fixes from Jason Wessel:
"These have been around since 3.17 and in kgdb-next for the last 9
weeks and some will go back to -stable.
Summary of changes:
Cleanups
- kdb: Remove unused command flags, repeat flags and KDB_REPEAT_NONE
Fixes
- kgdb/kdb: Allow access on a single core, if a CPU round up is
deemed impossible, which will allow inspection of the now "trashed"
kernel
- kdb: Add enable mask for the command groups
- kdb: access controls to restrict sensitive commands"
* tag 'for_linus-3.19-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/kgdb:
kernel/debug/debug_core.c: Logging clean-up
kgdb: timeout if secondary CPUs ignore the roundup
kdb: Allow access to sensitive commands to be restricted by default
kdb: Add enable mask for groups of commands
kdb: Categorize kdb commands (similar to SysRq categorization)
kdb: Remove KDB_REPEAT_NONE flag
kdb: Use KDB_REPEAT_* values as flags
kdb: Rename kdb_register_repeat() to kdb_register_flags()
kdb: Rename kdb_repeat_t to kdb_cmdflags_t, cmd_repeat to cmd_flags
kdb: Remove currently unused kdbtab_t->cmd_flags
Currently if DEBUG_MUTEXES is enabled, the mutex->owner field is only
cleared iff debug_locks is active. This exposes a race to other users of
the field where the mutex->owner may be still set to a stale value,
potentially upsetting mutex_spin_on_owner() among others.
References: https://bugs.freedesktop.org/show_bug.cgi?id=87955
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Davidlohr Bueso <dave@stgolabs.net>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1420540175-30204-1-git-send-email-chris@chris-wilson.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The dl_runtime_exceeded() function is supposed to ckeck if
a SCHED_DEADLINE task must be throttled, by checking if its
current runtime is <= 0. However, it also checks if the
scheduling deadline has been missed (the current time is
larger than the current scheduling deadline), further
decreasing the runtime if this happens.
This "double accounting" is wrong:
- In case of partitioned scheduling (or single CPU), this
happens if task_tick_dl() has been called later than expected
(due to small HZ values). In this case, the current runtime is
also negative, and replenish_dl_entity() can take care of the
deadline miss by recharging the current runtime to a value smaller
than dl_runtime
- In case of global scheduling on multiple CPUs, scheduling
deadlines can be missed even if the task did not consume more
runtime than expected, hence penalizing the task is wrong
This patch fix this problem by throttling a SCHED_DEADLINE task
only when its runtime becomes negative, and not modifying the runtime
Signed-off-by: Luca Abeni <luca.abeni@unitn.it>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Juri Lelli <juri.lelli@gmail.com>
Cc: <stable@vger.kernel.org>
Cc: Dario Faggioli <raistlin@linux.it>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1418813432-20797-3-git-send-email-luca.abeni@unitn.it
Signed-off-by: Ingo Molnar <mingo@kernel.org>
According to global EDF, tasks should be migrated between runqueues
without checking if their scheduling deadlines and runtimes are valid.
However, SCHED_DEADLINE currently performs such a check:
a migration happens doing:
deactivate_task(rq, next_task, 0);
set_task_cpu(next_task, later_rq->cpu);
activate_task(later_rq, next_task, 0);
which ends up calling dequeue_task_dl(), setting the new CPU, and then
calling enqueue_task_dl().
enqueue_task_dl() then calls enqueue_dl_entity(), which calls
update_dl_entity(), which can modify scheduling deadline and runtime,
breaking global EDF scheduling.
As a result, some of the properties of global EDF are not respected:
for example, a taskset {(30, 80), (40, 80), (120, 170)} scheduled on
two cores can have unbounded response times for the third task even
if 30/80+40/80+120/170 = 1.5809 < 2
This can be fixed by invoking update_dl_entity() only in case of
wakeup, or if this is a new SCHED_DEADLINE task.
Signed-off-by: Luca Abeni <luca.abeni@unitn.it>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Juri Lelli <juri.lelli@gmail.com>
Cc: <stable@vger.kernel.org>
Cc: Dario Faggioli <raistlin@linux.it>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1418813432-20797-2-git-send-email-luca.abeni@unitn.it
Signed-off-by: Ingo Molnar <mingo@kernel.org>
In effective_load, we have (long w * unsigned long tg->shares) / long W,
when w is negative, it is cast to unsigned long and hence the product is
insanely large. Fix this by casting tg->shares to long.
Reported-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Yuyang Du <yuyang.du@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Dave Jones <davej@redhat.com>
Cc: Andrey Ryabinin <a.ryabinin@samsung.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20141219002956.GA25405@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
On x86_64, at least, task_pt_regs may be only partially initialized
in many contexts, so x86_64 should not use it without extra care
from interrupt context, let alone NMI context.
This will allow x86_64 to override the logic and will supply some
scratch space to use to make a cleaner copy of user regs.
Tested-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: chenggang.qcg@taobao.com
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Jean Pihet <jean.pihet@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mark Salter <msalter@redhat.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/e431cd4c18c2e1c44c774f10758527fb2d1025c4.1420396372.git.luto@amacapital.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
wait_consider_task() checks EXIT_ZOMBIE after EXIT_DEAD/EXIT_TRACE and
both checks can fail if we race with EXIT_ZOMBIE -> EXIT_DEAD/EXIT_TRACE
change in between, gcc needs to reload p->exit_state after
security_task_wait(). In this case ->notask_error will be wrongly
cleared and do_wait() can hang forever if it was the last eligible
child.
Many thanks to Arne who carefully investigated the problem.
Note: this bug is very old but it was pure theoretical until commit
b3ab03160d ("wait: completely ignore the EXIT_DEAD tasks"). Before
this commit "-O2" was probably enough to guarantee that compiler won't
read ->exit_state twice.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reported-by: Arne Goedeke <el@laramies.com>
Tested-by: Arne Goedeke <el@laramies.com>
Cc: <stable@vger.kernel.org> [3.15+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Verify that the frequency value from userspace is valid and makes sense.
Unverified values can cause overflows later on.
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
[jstultz: Fix up bug for negative values and drop redunent cap check]
Signed-off-by: John Stultz <john.stultz@linaro.org>
An unvalidated user input is multiplied by a constant, which can result in
an undefined behaviour for large values. While this is validated later,
we should avoid triggering undefined behaviour.
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
[jstultz: include trivial milisecond->microsecond correction noticed
by Andy]
Signed-off-by: John Stultz <john.stultz@linaro.org>
Pull audit fix from Paul Moore:
"One audit patch to resolve a panic/oops when recording filenames in
the audit log, see the mail archive link below.
The fix isn't as nice as I would like, as it involves an allocate/copy
of the filename, but it solves the problem and the overhead should
only affect users who have configured audit rules involving file
names.
We'll revisit this issue with future kernels in an attempt to make
this suck less, but in the meantime I think this fix should go into
the next release of v3.19-rcX.
[ https://marc.info/?t=141986927600001&r=1&w=2 ]"
* 'upstream' of git://git.infradead.org/users/pcmoore/audit:
audit: create private file name copies when auditing inodes
Pull networking fixes from David Miller:
1) Fix double SKB free in bluetooth 6lowpan layer, from Jukka Rissanen.
2) Fix receive checksum handling in enic driver, from Govindarajulu
Varadarajan.
3) Fix NAPI poll list corruption in virtio_net and caif_virtio, from
Herbert Xu. Also, add code to detect drivers that have this mistake
in the future.
4) Fix doorbell endianness handling in mlx4 driver, from Amir Vadai.
5) Don't clobber IP6CB() before xfrm6_policy_check() is called in TCP
input path,f rom Nicolas Dichtel.
6) Fix MPLS action validation in openvswitch, from Pravin B Shelar.
7) Fix double SKB free in vxlan driver, also from Pravin.
8) When we scrub a packet, which happens when we are switching the
context of the packet (namespace, etc.), we should reset the
secmark. From Thomas Graf.
9) ->ndo_gso_check() needs to do more than return true/false, it also
has to allow the driver to clear netdev feature bits in order for
the caller to be able to proceed properly. From Jesse Gross.
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (62 commits)
genetlink: A genl_bind() to an out-of-range multicast group should not WARN().
netlink/genetlink: pass network namespace to bind/unbind
ne2k-pci: Add pci_disable_device in error handling
bonding: change error message to debug message in __bond_release_one()
genetlink: pass multicast bind/unbind to families
netlink: call unbind when releasing socket
netlink: update listeners directly when removing socket
genetlink: pass only network namespace to genl_has_listeners()
netlink: rename netlink_unbind() to netlink_undo_bind()
net: Generalize ndo_gso_check to ndo_features_check
net: incorrect use of init_completion fixup
neigh: remove next ptr from struct neigh_table
net: xilinx: Remove unnecessary temac_property in the driver
net: phy: micrel: use generic config_init for KSZ8021/KSZ8031
net/core: Handle csum for CHECKSUM_COMPLETE VXLAN forwarding
openvswitch: fix odd_ptr_err.cocci warnings
Bluetooth: Fix accepting connections when not using mgmt
Bluetooth: Fix controller configuration with HCI_QUIRK_INVALID_BDADDR
brcmfmac: Do not crash if platform data is not populated
ipw2200: select CFG80211_WEXT
...
