Pull scheduler fixes from Thomas Gleixner:
"Three small fixes in the scheduler/core:
- use after free in the numa code
- crash in the numa init code
- a simple spelling fix"
* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
pid: Fix spelling in comments
sched/numa: Fix use-after-free bug in the task_numa_compare
sched: Fix crash in sched_init_numa()
Pull perf fixes from Thomas Gleixner:
"This is much bigger than typical fixes, but Peter found a category of
races that spurred more fixes and more debugging enhancements. Work
started before the merge window, but got finished only now.
Aside of that this contains the usual small fixes to perf and tools.
Nothing particular exciting"
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (43 commits)
perf: Remove/simplify lockdep annotation
perf: Synchronously clean up child events
perf: Untangle 'owner' confusion
perf: Add flags argument to perf_remove_from_context()
perf: Clean up sync_child_event()
perf: Robustify event->owner usage and SMP ordering
perf: Fix STATE_EXIT usage
perf: Update locking order
perf: Remove __free_event()
perf/bpf: Convert perf_event_array to use struct file
perf: Fix NULL deref
perf/x86: De-obfuscate code
perf/x86: Fix uninitialized value usage
perf: Fix race in perf_event_exit_task_context()
perf: Fix orphan hole
perf stat: Do not clean event's private stats
perf hists: Fix HISTC_MEM_DCACHELINE width setting
perf annotate browser: Fix behaviour of Shift-Tab with nothing focussed
perf tests: Remove wrong semicolon in while loop in CQM test
perf: Synchronously free aux pages in case of allocation failure
...
Pull locking fix from Thomas Gleixner:
"A single commit, which makes the rtmutex.wait_lock an irq safe lock.
This prevents a potential deadlock which can be triggered by the rcu
boosting code from rcu_read_unlock()"
* 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
rtmutex: Make wait_lock irq safe
Pull IRQ fixes from Ingo Molnar:
"Mostly irqchip driver fixes, but also an irq core crash fix and a
build fix"
* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
irqchip/mxs: Add missing set_handle_irq()
irqchip/atmel-aic: Fix wrong bit operation for IRQ priority
irqchip/gic-v3-its: Recompute the number of pages on page size change
base: Export platform_msi_domain_[alloc,free]_irqs
of: MSI: Simplify irqdomain lookup
irqdomain: Allow domain lookup with DOMAIN_BUS_WIRED token
irqchip: Fix dependencies for archs w/o HAS_IOMEM
irqchip/s3c24xx: Mark init_eint as __maybe_unused
genirq: Validate action before dereferencing it in handle_irq_event_percpu()
- Fix a recent cpuidle core regression that broke suspend-to-idle
on all systems where cpuidle drivers don't provide ->enter_freeze
callbacks for any states (Sudeep Holla).
- Drop an unnecessary symbol definition from the cpuidle core code
handling coupled CPU cores (Anders Roxell).
- Fix a race condition related to governor initialization and removal
in the cpufreq core (Viresh Kumar).
- Clean up the cpufreq core to use list_is_last() for checking if
the given policy object is the last element of a list instead of
open coding that in a clumsy way (Gautham R Shenoy).
- Fix compiler warnings in the pxa2xx and cpufreq-dt cpufreq drivers
(Arnd Bergmann).
- Fix two locking issues and clean up a comment in the generic power
domains framework (Ulf Hansson, Marek Szyprowski, Moritz Fischer).
- Fix the error code path of one function in the ACPI-based PCI
hotplug framework (ACPIPHP) that forgets to release a lock
acquired previously (Insu Yun).
- Drop the ACPI backlight blacklist entry for Dell Inspiron 5737
that is not necessary any more (Hans de Goede).
- Clean up the top-level PM Kconfig to stop requiring APM emulation
to depend on PM which in fact isn't necessary (Arnd Bergmann).
/
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Merge tag 'pm+acpi-4.5-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull power management and ACPI fixes from Rafael Wysocki:
"These are: cpuidle fixes (including one fix for a recent regression),
cpufreq fixes (including fixes for two issues introduced during the
4.2 cycle), generic power domains framework fixes (two locking fixes
and one cleanup), one locking fix in the ACPI-based PCI hotplug
framework (ACPIPHP), removal of one ACPI backlight blacklist entry
that isn't necessary any more and a PM Kconfig cleanup.
Specifics:
- Fix a recent cpuidle core regression that broke suspend-to-idle on
all systems where cpuidle drivers don't provide ->enter_freeze
callbacks for any states (Sudeep Holla).
- Drop an unnecessary symbol definition from the cpuidle core code
handling coupled CPU cores (Anders Roxell).
- Fix a race condition related to governor initialization and removal
in the cpufreq core (Viresh Kumar).
- Clean up the cpufreq core to use list_is_last() for checking if the
given policy object is the last element of a list instead of open
coding that in a clumsy way (Gautham R Shenoy).
- Fix compiler warnings in the pxa2xx and cpufreq-dt cpufreq drivers
(Arnd Bergmann).
- Fix two locking issues and clean up a comment in the generic power
domains framework (Ulf Hansson, Marek Szyprowski, Moritz Fischer).
- Fix the error code path of one function in the ACPI-based PCI
hotplug framework (ACPIPHP) that forgets to release a lock acquired
previously (Insu Yun).
- Drop the ACPI backlight blacklist entry for Dell Inspiron 5737 that
is not necessary any more (Hans de Goede).
- Clean up the top-level PM Kconfig to stop requiring APM emulation
to depend on PM which in fact isn't necessary (Arnd Bergmann)"
* tag 'pm+acpi-4.5-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
cpufreq: cpufreq-dt: avoid uninitialized variable warnings:
cpufreq: pxa2xx: fix pxa_cpufreq_change_voltage prototype
PM: APM_EMULATION does not depend on PM
cpufreq: Use list_is_last() to check last entry of the policy list
cpufreq: Fix NULL reference crash while accessing policy->governor_data
cpuidle: coupled: remove unused define cpuidle_coupled_lock
PM / Domains: Fix typo in comment
PM / Domains: Fix potential deadlock while adding/removing subdomains
ACPI / PCI / hotplug: unlock in error path in acpiphp_enable_slot()
ACPI: Revert "ACPI / video: Add Dell Inspiron 5737 to the blacklist"
cpuidle: fix fallback mechanism for suspend to idle in absence of enter_freeze
PM / domains: fix lockdep issue for all subdomains
* pm-cpuidle:
cpuidle: coupled: remove unused define cpuidle_coupled_lock
cpuidle: fix fallback mechanism for suspend to idle in absence of enter_freeze
* pm-cpufreq:
cpufreq: cpufreq-dt: avoid uninitialized variable warnings:
cpufreq: pxa2xx: fix pxa_cpufreq_change_voltage prototype
cpufreq: Use list_is_last() to check last entry of the policy list
cpufreq: Fix NULL reference crash while accessing policy->governor_data
* pm-domains:
PM / Domains: Fix typo in comment
PM / Domains: Fix potential deadlock while adding/removing subdomains
PM / domains: fix lockdep issue for all subdomains
* pm-sleep:
PM: APM_EMULATION does not depend on PM
Pull security layer fixes from James Morris:
"The keys patch fixes a bug which is breaking kerberos, and the seccomp
fix addresses a no_new_privs bypass"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security:
KEYS: Only apply KEY_FLAG_KEEP to a key if a parent keyring has it set
seccomp: always propagate NO_NEW_PRIVS on tsync
Now that the perf_event_ctx_lock_nested() call has moved from
put_event() into perf_event_release_kernel() the first reason is no
longer valid as that can no longer happen.
The second reason seems to have been invalidated when Al Viro made fput()
unconditionally async in the following commit:
4a9d4b024a ("switch fput to task_work_add")
such that munmap()->fput()->release()->perf_release() would no longer happen.
Therefore, remove the annotation. This should increase the efficiency
of lockdep coverage of perf locking.
Suggested-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.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>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The orphan cleanup workqueue doesn't always catch orphans, for example,
if they never schedule after they are orphaned. IOW, the event leak is
still very real. It also wouldn't work for kernel counters.
Doing it synchonously is a little hairy due to lock inversion issues,
but is made to work.
Patch based on work by Alexander Shishkin.
Suggested-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.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: vince@deater.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
There are two concepts of owner wrt an event and they are conflated:
- event::owner / event::owner_list,
used by prctl(.option = PR_TASK_PERF_EVENTS_{EN,DIS}ABLE).
- the 'owner' of the event object, typically the file descriptor.
Currently these two concepts are conflated, which gives trouble with
scm_rights passing of file descriptors. Passing the event and then
closing the creating task would render the event 'orphan' and would
have it cleared out. Unlikely what is expectd.
This patch untangles these two concepts by using PERF_EVENT_STATE_EXIT
to denote the second type.
Reported-by: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.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>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
In preparation to adding more options, convert the boolean argument
into a flags word.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.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>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
sync_child_event() has outgrown its purpose, it does far too much.
Bring it back to its named purpose.
Rename __perf_event_exit_task() to perf_event_exit_event() to better
reflect what it does and move the event->state assignment under the
ctx->lock, like state changes ought to be.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.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>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Use smp_store_release() to clear event->owner and
lockless_dereference() to observe it. Further use READ_ONCE() for all
lockless reads.
This changes perf_remove_from_owner() to leave event->owner cleared.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.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>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
We should never attempt to enable a STATE_EXIT event.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.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>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
There is but a single caller, remove the function - we already have
_free_event(), the extra indirection is nonsensical..
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.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>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The first is a cut and paste issue that changed the amount of stack
to skip when tracing a stack dump from 0 to 6, which basically made
the stack disappear for small stack traces.
The second fix is just removing an unused field in a struct that is no
longer used, and currently just wastes space.
The third is another cut-and-paste fix that had a tracepoint recording
the wrong field (it was recording the previous field a second time).
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Merge tag 'trace-v4.5-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull minor tracing fixes from Steven Rostedt:
"This includes three minor fixes, mostly due to cut-and-paste issues.
The first is a cut and paste issue that changed the amount of stack to
skip when tracing a stack dump from 0 to 6, which basically made the
stack disappear for small stack traces.
The second fix is just removing an unused field in a struct that is no
longer used, and currently just wastes space.
The third is another cut-and-paste fix that had a tracepoint recording
the wrong field (it was recording the previous field a second time)"
* tag 'trace-v4.5-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
tracing/dma-buf/fence: Fix timeline str value on fence_annotate_wait_on
ftrace: Remove unused nr_trampolines var
tracing: Fix stacktrace skip depth in trace_buffer_unlock_commit_regs()
There is a race between perf_event_exit_task_context() and
orphans_remove_work() which results in a use-after-free.
We mark ctx->task with TASK_TOMBSTONE to indicate a context is
'dead', under ctx->lock. After which point event_function_call()
on any event of that context will NOP
A concurrent orphans_remove_work() will only hold ctx->mutex for
the list iteration and not serialize against this. Therefore its
possible that orphans_remove_work()'s perf_remove_from_context()
call will fail, but we'll continue to free the event, with the
result of free'd memory still being on lists and everything.
Once perf_event_exit_task_context() gets around to acquiring
ctx->mutex it too will iterate the event list, encounter the
already free'd event and proceed to free it _again_. This fails
with the WARN in free_event().
Plug the race by having perf_event_exit_task_context() hold
ctx::mutex over the whole tear-down, thereby 'naturally'
serializing against all other sites, including the orphan work.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.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>
Cc: alexander.shishkin@linux.intel.com
Cc: dsahern@gmail.com
Cc: namhyung@kernel.org
Link: http://lkml.kernel.org/r/20160125130954.GY6357@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
We should set event->owner before we install the event,
otherwise there is a hole where the target task can fork() and
we'll not inherit the event because it thinks the event is
orphaned.
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The APM emulation code does multiple things, and some of them depend on
PM_SLEEP, while the battery management does not. However, selecting
the symbol like SHARPSL_PM does causes a Kconfig warning:
warning: (SHARPSL_PM && PMAC_APM_EMU) selects APM_EMULATION which has unmet direct dependencies (PM && SYS_SUPPORTS_APM_EMULATION)
From all I can tell, this is completely harmless, and we can simply allow
APM_EMULATION to be enabled here, even if PM is not.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Before this patch, a process with some permissive seccomp filter
that was applied by root without NO_NEW_PRIVS was able to add
more filters to itself without setting NO_NEW_PRIVS by setting
the new filter from a throwaway thread with NO_NEW_PRIVS.
Signed-off-by: Jann Horn <jann@thejh.net>
Cc: stable@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Let's take the (outlandish) example of an interrupt controller
capable of handling both wired interrupts and PCI MSIs.
With the current code, the PCI MSI domain is going to be tagged
with DOMAIN_BUS_PCI_MSI, and the wired domain with DOMAIN_BUS_ANY.
Things get hairy when we start looking up the domain for a wired
interrupt (typically when creating it based on some firmware
information - DT or ACPI).
In irq_create_fwspec_mapping(), we perform the lookup using
DOMAIN_BUS_ANY, which is actually used as a wildcard. This gives
us one chance out of two to end up with the wrong domain, and
we try to configure a wired interrupt with the MSI domain.
Everything grinds to a halt pretty quickly.
What we really need to do is to start looking for a domain that
would uniquely identify a wired interrupt domain, and only use
DOMAIN_BUS_ANY as a fallback.
In order to solve this, let's introduce a new DOMAIN_BUS_WIRED
token, which is going to be used exactly as described above.
Of course, this depends on the irqchip to setup the domain
bus_token, and nobody had to implement this so far.
Only so far.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Frank Rowand <frowand.list@gmail.com>
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Link: http://lkml.kernel.org/r/1453816347-32720-2-git-send-email-marc.zyngier@arm.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Sasha reported a lockdep splat about a potential deadlock between RCU boosting
rtmutex and the posix timer it_lock.
CPU0 CPU1
rtmutex_lock(&rcu->rt_mutex)
spin_lock(&rcu->rt_mutex.wait_lock)
local_irq_disable()
spin_lock(&timer->it_lock)
spin_lock(&rcu->mutex.wait_lock)
--> Interrupt
spin_lock(&timer->it_lock)
This is caused by the following code sequence on CPU1
rcu_read_lock()
x = lookup();
if (x)
spin_lock_irqsave(&x->it_lock);
rcu_read_unlock();
return x;
We could fix that in the posix timer code by keeping rcu read locked across
the spinlocked and irq disabled section, but the above sequence is common and
there is no reason not to support it.
Taking rt_mutex.wait_lock irq safe prevents the deadlock.
Reported-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
parallel to mutex_{lock,unlock,trylock,is_locked,lock_nested},
inode_foo(inode) being mutex_foo(&inode->i_mutex).
Please, use those for access to ->i_mutex; over the coming cycle
->i_mutex will become rwsem, with ->lookup() done with it held
only shared.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Pull more vfs updates from Al Viro:
"Embarrassing braino fix + pipe page accounting + fixing an eyesore in
find_filesystem() (checking that s1 is equal to prefix of s2 of given
length can be done in many ways, but "compare strlen(s1) with length
and then do strncmp()" is not a good one...)"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
[regression] fix braino in fs/dlm/user.c
pipe: limit the per-user amount of pages allocated in pipes
find_filesystem(): simplify comparison
The following message can be observed on the Ubuntu v3.13.0-65 with KASan
backported:
==================================================================
BUG: KASan: use after free in task_numa_find_cpu+0x64c/0x890 at addr ffff880dd393ecd8
Read of size 8 by task qemu-system-x86/3998900
=============================================================================
BUG kmalloc-128 (Tainted: G B ): kasan: bad access detected
-----------------------------------------------------------------------------
INFO: Allocated in task_numa_fault+0xc1b/0xed0 age=41980 cpu=18 pid=3998890
__slab_alloc+0x4f8/0x560
__kmalloc+0x1eb/0x280
task_numa_fault+0xc1b/0xed0
do_numa_page+0x192/0x200
handle_mm_fault+0x808/0x1160
__do_page_fault+0x218/0x750
do_page_fault+0x1a/0x70
page_fault+0x28/0x30
SyS_poll+0x66/0x1a0
system_call_fastpath+0x1a/0x1f
INFO: Freed in task_numa_free+0x1d2/0x200 age=62 cpu=18 pid=0
__slab_free+0x2ab/0x3f0
kfree+0x161/0x170
task_numa_free+0x1d2/0x200
finish_task_switch+0x1d2/0x210
__schedule+0x5d4/0xc60
schedule_preempt_disabled+0x40/0xc0
cpu_startup_entry+0x2da/0x340
start_secondary+0x28f/0x360
Call Trace:
[<ffffffff81a6ce35>] dump_stack+0x45/0x56
[<ffffffff81244aed>] print_trailer+0xfd/0x170
[<ffffffff8124ac36>] object_err+0x36/0x40
[<ffffffff8124cbf9>] kasan_report_error+0x1e9/0x3a0
[<ffffffff8124d260>] kasan_report+0x40/0x50
[<ffffffff810dda7c>] ? task_numa_find_cpu+0x64c/0x890
[<ffffffff8124bee9>] __asan_load8+0x69/0xa0
[<ffffffff814f5c38>] ? find_next_bit+0xd8/0x120
[<ffffffff810dda7c>] task_numa_find_cpu+0x64c/0x890
[<ffffffff810de16c>] task_numa_migrate+0x4ac/0x7b0
[<ffffffff810de523>] numa_migrate_preferred+0xb3/0xc0
[<ffffffff810e0b88>] task_numa_fault+0xb88/0xed0
[<ffffffff8120ef02>] do_numa_page+0x192/0x200
[<ffffffff81211038>] handle_mm_fault+0x808/0x1160
[<ffffffff810d7dbd>] ? sched_clock_cpu+0x10d/0x160
[<ffffffff81068c52>] ? native_load_tls+0x82/0xa0
[<ffffffff81a7bd68>] __do_page_fault+0x218/0x750
[<ffffffff810c2186>] ? hrtimer_try_to_cancel+0x76/0x160
[<ffffffff81a6f5e7>] ? schedule_hrtimeout_range_clock.part.24+0xf7/0x1c0
[<ffffffff81a7c2ba>] do_page_fault+0x1a/0x70
[<ffffffff81a772e8>] page_fault+0x28/0x30
[<ffffffff8128cbd4>] ? do_sys_poll+0x1c4/0x6d0
[<ffffffff810e64f6>] ? enqueue_task_fair+0x4b6/0xaa0
[<ffffffff810233c9>] ? sched_clock+0x9/0x10
[<ffffffff810cf70a>] ? resched_task+0x7a/0xc0
[<ffffffff810d0663>] ? check_preempt_curr+0xb3/0x130
[<ffffffff8128b5c0>] ? poll_select_copy_remaining+0x170/0x170
[<ffffffff810d3bc0>] ? wake_up_state+0x10/0x20
[<ffffffff8112a28f>] ? drop_futex_key_refs.isra.14+0x1f/0x90
[<ffffffff8112d40e>] ? futex_requeue+0x3de/0xba0
[<ffffffff8112e49e>] ? do_futex+0xbe/0x8f0
[<ffffffff81022c89>] ? read_tsc+0x9/0x20
[<ffffffff8111bd9d>] ? ktime_get_ts+0x12d/0x170
[<ffffffff8108f699>] ? timespec_add_safe+0x59/0xe0
[<ffffffff8128d1f6>] SyS_poll+0x66/0x1a0
[<ffffffff81a830dd>] system_call_fastpath+0x1a/0x1f
As commit 1effd9f193 ("sched/numa: Fix unsafe get_task_struct() in
task_numa_assign()") points out, the rcu_read_lock() cannot protect the
task_struct from being freed in the finish_task_switch(). And the bug
happens in the process of calculation of imp which requires the access of
p->numa_faults being freed in the following path:
do_exit()
current->flags |= PF_EXITING;
release_task()
~~delayed_put_task_struct()~~
schedule()
...
...
rq->curr = next;
context_switch()
finish_task_switch()
put_task_struct()
__put_task_struct()
task_numa_free()
The fix here to get_task_struct() early before end of dst_rq->lock to
protect the calculation process and also put_task_struct() in the
corresponding point if finally the dst_rq->curr somehow cannot be
assigned.
Additional credit to Liang Chen who helped fix the error logic and add the
put_task_struct() to the place it missed.
Signed-off-by: Gavin Guo <gavin.guo@canonical.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: jay.vosburgh@canonical.com
Cc: liang.chen@canonical.com
Link: http://lkml.kernel.org/r/1453264618-17645-1-git-send-email-gavin.guo@canonical.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Commit 51164251f5 "sched / idle: Drop default_idle_call() fallback
from call_cpuidle()" made find_deepest_state() return non-negative
value and check all the states with index > 0. Also as a result,
find_deepest_state() returns 0 even when enter_freeze callbacks are not
implemented and enter_freeze_proper() is called which ends up crashing
the kernel.
This patch updates the check for index > 0 in cpuidle_enter_freeze and
cpuidle_idle_call(when idle_should_freeze is true) to restore the
suspend-to-idle functionality in absence of enter_freeze callback.
Fixes: 51164251f5 "sched / idle: Drop default_idle_call() fallback from call_cpuidle()"
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Merge third patch-bomb from Andrew Morton:
"I'm pretty much done for -rc1 now:
- the rest of MM, basically
- lib/ updates
- checkpatch, epoll, hfs, fatfs, ptrace, coredump, exit
- cpu_mask simplifications
- kexec, rapidio, MAINTAINERS etc, etc.
- more dma-mapping cleanups/simplifications from hch"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (109 commits)
MAINTAINERS: add/fix git URLs for various subsystems
mm: memcontrol: add "sock" to cgroup2 memory.stat
mm: memcontrol: basic memory statistics in cgroup2 memory controller
mm: memcontrol: do not uncharge old page in page cache replacement
Documentation: cgroup: add memory.swap.{current,max} description
mm: free swap cache aggressively if memcg swap is full
mm: vmscan: do not scan anon pages if memcg swap limit is hit
swap.h: move memcg related stuff to the end of the file
mm: memcontrol: replace mem_cgroup_lruvec_online with mem_cgroup_online
mm: vmscan: pass memcg to get_scan_count()
mm: memcontrol: charge swap to cgroup2
mm: memcontrol: clean up alloc, online, offline, free functions
mm: memcontrol: flatten struct cg_proto
mm: memcontrol: rein in the CONFIG space madness
net: drop tcp_memcontrol.c
mm: memcontrol: introduce CONFIG_MEMCG_LEGACY_KMEM
mm: memcontrol: allow to disable kmem accounting for cgroup2
mm: memcontrol: account "kmem" consumers in cgroup2 memory controller
mm: memcontrol: move kmem accounting code to CONFIG_MEMCG
mm: memcontrol: separate kmem code from legacy tcp accounting code
...
We are currently using asynchronous deallocation in the error path in
AUX mmap code, which is unnecessary and also presents a problem for users
that wish to probe for the biggest possible buffer size they can get:
they'll get -EINVAL on all subsequent attemts to allocate a smaller
buffer before the asynchronous deallocation callback frees up the pages
from the previous unsuccessful attempt.
Currently, gdb does that for allocating AUX buffers for Intel PT traces.
More specifically, overwrite mode of AUX pmus that don't support hardware
sg (some implementations of Intel PT, for instance) is limited to only
one contiguous high order allocation for its buffer and there is no way
of knowing its size without trying.
This patch changes error path freeing to be synchronous as there won't
be any contenders for the AUX pages at that point.
Reported-by: Markus Metzger <markus.t.metzger@intel.com>
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.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: vince@deater.net
Link: http://lkml.kernel.org/r/1453216469-9509-1-git-send-email-alexander.shishkin@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
There is a race against perf_event_exit_task() vs
event_function_call(),find_get_context(),perf_install_in_context()
(iow, everyone).
Since there is no permanent marker on a context that its dead, it is
quite possible that we access (and even modify) a context after its
passed through perf_event_exit_task().
For instance, find_get_context() might find the context still
installed, but by the time we get to perf_install_in_context() it
might already have passed through perf_event_exit_task() and be
considered dead, we will however still add the event to it.
Solve this by marking a ctx dead by setting its ctx->task value to -1,
it must be !0 so we still know its a (former) task context.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.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>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
There is one common bug left in all the event_function_call() users,
between loading ctx->task and getting to the remote_function(),
ctx->task can already have been changed.
Therefore we need to double check and retry if ctx->task != current.
Insert another trampoline specific to event_function_call() that
checks for this and further validates state. This also allows getting
rid of the active/inactive functions.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.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>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The perf_remove_from_context() usage in __perf_event_exit_task() is
different from the other usages in that this site has already
detached and scheduled out the task context.
This will stand in the way of stronger assertions checking the (task)
context scheduling invariants.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.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>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
There is a very nasty problem wrt disabling the perf task scheduling
hooks.
Currently we {set,clear} ctx->is_active on every
__perf_event_task_sched_{in,out}, _however_ this means that if we
disable these calls we'll have task contexts with ->is_active set that
are not active and 'active' task contexts without ->is_active set.
This can result in event_function_call() looping on the ctx->is_active
condition basically indefinitely.
Resolve this by changing things such that contexts without events do
not set ->is_active like we used to. From this invariant it trivially
follows that if there are no (task) events, every task ctx is inactive
and disabling the context switch hooks is harmless.
This leaves two places that need attention (and already had
accumulated weird and wonderful hacks to work around, without
recognising this actual problem).
Namely:
- perf_install_in_context() will need to deal with installing events
in an inactive context, meaning it cannot rely on ctx-is_active for
its IPIs.
- perf_remove_from_context() will have to mark a context as inactive
when it removes the last event.
For specific detail, see the patch/comments.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.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>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
For no apparent reason and to great confusion the rules for
ctx->is_active and cpuctx->task_ctx are different. This means that its
not always possible to find all active (task) contexts.
Fix this such that if ctx->is_active gets set, we also set (or verify)
cpuctx->task_ctx.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.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>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
It doesn't make sense to take up-to _4_ references on
perf_sched_events() per event, avoid doing this.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.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>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Like perf_enable_on_exec(), perf_event_enable() event scheduling has problems
respecting the context hierarchy when trying to schedule events (for
example, it will try and add a pinned event without first removing
existing flexible events).
So simplify it by using the new ctx_resched() call which will DTRT.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.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>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
We have a function that does exactly what we want here, use it. This
reduces the amount of cpuctx->task_ctx muckery.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.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>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
There are two problems with the current perf_enable_on_exec() event
scheduling:
- the newly enabled events will be immediately scheduled
irrespective of their ctx event list order.
- there's a hole in the ctx->lock between scheduling the events
out and putting them back on.
Esp. the latter issue is a real problem because a hole in event
scheduling leaves the thing in an observable inconsistent state,
confusing things.
Fix both issues by first doing the enable iteration and at the end,
when there are newly enabled events, reschedule the ctx in one go.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.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>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The comment here is horribly out of date, remove it.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.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>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
There is a comment that states that perf_event_context_sched_in() will
also switch in the cgroup events, I cannot find it does so. Therefore
all the resulting logic goes out the window too.
Clean that up.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.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>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
There appears to be a problem in __perf_event_task_sched_in() wrt
cgroup event scheduling.
The normal event scheduling order is:
CPU pinned
Task pinned
CPU flexible
Task flexible
And since perf_cgroup_sched*() only schedules the cpu context, we must
call this _before_ adding the task events.
Note: double check what happens on the ctx switch optimization where
the task ctx isn't scheduled.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.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>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
- Modify the driver core and the USB subsystem to allow USB devices
to stay suspended over system suspend/resume cycles if they have
been runtime-suspended already beforehand and fix some bugs on
top of these changes (Tomeu Vizoso, Rafael Wysocki).
- Update ACPICA to upstream revision 20160108, including updates
of the ACPICA's copyright notices, a code fixup resulting from
a regression fix that was necessary in the upstream code only
(the regression fixed by it has never been present in Linux)
and a compiler warning fix (Bob Moore, Lv Zheng).
- Fix a recent regression in the cpuidle menu governor that broke
it on practically all architectures other than x86 and make a
couple of optimizations on top of that fix (Rafael Wysocki).
- Clean up the selection of cpuidle governors depending on whether
or not the kernel is configured for tickless systems (Jean Delvare).
- Revert a recent commit that introduced a regression in the ACPI
backlight driver, address the problem it attempted to fix in a
different way and revert one more cosmetic change depending on
the problematic commit (Hans de Goede).
- Add two more ACPI backlight quirks (Hans de Goede).
- Fix a few minor problems in the core devfreq code, clean it up
a bit and update the MAINTAINERS information related to it
(Chanwoo Choi, MyungJoo Ham).
- Improve an error message in the ACPI fan driver (Andy Lutomirski).
- Fix a recent build regression in the cpupower tool (Shreyas Prabhu).
/
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Merge tag 'pm+acpi-4.5-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull more power management and ACPI updates from Rafael Wysocki:
"This includes fixes on top of the previous batch of PM+ACPI updates
and some new material as well.
From the new material perspective the most significant are the driver
core changes that should allow USB devices to stay suspended over
system suspend/resume cycles if they have been runtime-suspended
already beforehand. Apart from that, ACPICA is updated to upstream
revision 20160108 (cosmetic mostly, but including one fixup on top of
the previous ACPICA update) and there are some devfreq updates the
didn't make it before (due to timing).
A few recent regressions are fixed, most importantly in the cpuidle
menu governor and in the ACPI backlight driver and some x86 platform
drivers depending on it.
Some more bugs are fixed and cleanups are made on top of that.
Specifics:
- Modify the driver core and the USB subsystem to allow USB devices
to stay suspended over system suspend/resume cycles if they have
been runtime-suspended already beforehand and fix some bugs on top
of these changes (Tomeu Vizoso, Rafael Wysocki).
- Update ACPICA to upstream revision 20160108, including updates of
the ACPICA's copyright notices, a code fixup resulting from a
regression fix that was necessary in the upstream code only (the
regression fixed by it has never been present in Linux) and a
compiler warning fix (Bob Moore, Lv Zheng).
- Fix a recent regression in the cpuidle menu governor that broke it
on practically all architectures other than x86 and make a couple
of optimizations on top of that fix (Rafael Wysocki).
- Clean up the selection of cpuidle governors depending on whether or
not the kernel is configured for tickless systems (Jean Delvare).
- Revert a recent commit that introduced a regression in the ACPI
backlight driver, address the problem it attempted to fix in a
different way and revert one more cosmetic change depending on the
problematic commit (Hans de Goede).
- Add two more ACPI backlight quirks (Hans de Goede).
- Fix a few minor problems in the core devfreq code, clean it up a
bit and update the MAINTAINERS information related to it (Chanwoo
Choi, MyungJoo Ham).
- Improve an error message in the ACPI fan driver (Andy Lutomirski).
- Fix a recent build regression in the cpupower tool (Shreyas
Prabhu)"
* tag 'pm+acpi-4.5-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (32 commits)
cpuidle: menu: Avoid pointless checks in menu_select()
sched / idle: Drop default_idle_call() fallback from call_cpuidle()
cpupower: Fix build error in cpufreq-info
cpuidle: Don't enable all governors by default
cpuidle: Default to ladder governor on ticking systems
time: nohz: Expose tick_nohz_enabled
ACPICA: Update version to 20160108
ACPICA: Silence a -Wbad-function-cast warning when acpi_uintptr_t is 'uintptr_t'
ACPICA: Additional 2016 copyright changes
ACPICA: Reduce regression fix divergence from upstream ACPICA
ACPI / video: Add disable_backlight_sysfs_if quirk for the Toshiba Satellite R830
ACPI / video: Revert "thinkpad_acpi: Use acpi_video_handles_brightness_key_presses()"
ACPI / video: Document acpi_video_handles_brightness_key_presses() a bit
ACPI / video: Fix using an uninitialized mutex / list_head in acpi_video_handles_brightness_key_presses()
ACPI / video: Revert "ACPI / video: driver must be registered before checking for keypresses"
ACPI / fan: Improve acpi_device_update_power error message
ACPI / video: Add disable_backlight_sysfs_if quirk for the Toshiba Portege R700
cpuidle: menu: Fix menu_select() for CPUIDLE_DRIVER_STATE_START == 0
MAINTAINERS: Add devfreq-event entry
MAINTAINERS: Add missing git repository and directory for devfreq
...
An unprivileged user can trigger an oops on a kernel with
CONFIG_CHECKPOINT_RESTORE.
proc_pid_cmdline_read takes mmap_sem for reading and obtains args + env
start/end values. These get sanity checked as follows:
BUG_ON(arg_start > arg_end);
BUG_ON(env_start > env_end);
These can be changed by prctl_set_mm. Turns out also takes the semaphore for
reading, effectively rendering it useless. This results in:
kernel BUG at fs/proc/base.c:240!
invalid opcode: 0000 [#1] SMP
Modules linked in: virtio_net
CPU: 0 PID: 925 Comm: a.out Not tainted 4.4.0-rc8-next-20160105dupa+ #71
Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
task: ffff880077a68000 ti: ffff8800784d0000 task.ti: ffff8800784d0000
RIP: proc_pid_cmdline_read+0x520/0x530
RSP: 0018:ffff8800784d3db8 EFLAGS: 00010206
RAX: ffff880077c5b6b0 RBX: ffff8800784d3f18 RCX: 0000000000000000
RDX: 0000000000000002 RSI: 00007f78e8857000 RDI: 0000000000000246
RBP: ffff8800784d3e40 R08: 0000000000000008 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000050
R13: 00007f78e8857800 R14: ffff88006fcef000 R15: ffff880077c5b600
FS: 00007f78e884a740(0000) GS:ffff88007b200000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: 00007f78e8361770 CR3: 00000000790a5000 CR4: 00000000000006f0
Call Trace:
__vfs_read+0x37/0x100
vfs_read+0x82/0x130
SyS_read+0x58/0xd0
entry_SYSCALL_64_fastpath+0x12/0x76
Code: 4c 8b 7d a8 eb e9 48 8b 9d 78 ff ff ff 4c 8b 7d 90 48 8b 03 48 39 45 a8 0f 87 f0 fe ff ff e9 d1 fe ff ff 4c 8b 7d 90 eb c6 0f 0b <0f> 0b 0f 0b 66 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00
RIP proc_pid_cmdline_read+0x520/0x530
---[ end trace 97882617ae9c6818 ]---
Turns out there are instances where the code just reads aformentioned
values without locking whatsoever - namely environ_read and get_cmdline.
Interestingly these functions look quite resilient against bogus values,
but I don't believe this should be relied upon.
The first patch gets rid of the oops bug by grabbing mmap_sem for
writing.
The second patch is optional and puts locking around aformentioned
consumers for safety. Consumers of other fields don't seem to benefit
from similar treatment and are left untouched.
This patch (of 2):
The code was taking the semaphore for reading, which does not protect
against readers nor concurrent modifications.
The problem could cause a sanity checks to fail in procfs's cmdline
reader, resulting in an OOPS.
Note that some functions perform an unlocked read of various mm fields,
but they seem to be fine despite possible modificaton.
Signed-off-by: Mateusz Guzik <mguzik@redhat.com>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Jarod Wilson <jarod@redhat.com>
Cc: Jan Stancek <jstancek@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Anshuman Khandual <anshuman.linux@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
