Peter Zijlstra [Tue, 17 Jan 2017 15:06:09 +0000 (16:06 +0100)]
locking/mutex: Fix lockdep_assert_held() fail
In commit:
659cf9f5824a ("locking/ww_mutex: Optimize ww-mutexes by waking at most one waiter for backoff when acquiring the lock")
I replaced a comment with a lockdep_assert_held(). However it turns out
we hide that lock from lockdep for hysterical raisins, which results
in the assertion always firing.
Remove the old debug code as lockdep will easily spot the abuse it was
meant to catch, which will make the lock visible to lockdep and make
the assertion work as intended.
Reported-by: Mike Galbraith <efault@gmx.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Nicolai Haehnle <Nicolai.Haehnle@amd.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Fixes: 659cf9f5824a ("locking/ww_mutex: Optimize ww-mutexes by waking at most one waiter for backoff when acquiring the lock") Link: http://lkml.kernel.org/r/20170117150609.GB32474@worktop Signed-off-by: Ingo Molnar <mingo@kernel.org>
locking/rtmutex: Flip unlikely() branch to likely() in __rt_mutex_slowlock()
Running my likely/unlikely profiler for 3 weeks on two production
machines, I discovered that the unlikely() test in
__rt_mutex_slowlock() checking if state is TASK_INTERRUPTIBLE is hit
100% of the time, making it a very likely case.
The reason is, on a vanilla kernel, the majority case of calling
rt_mutex() is from the futex code. This code is always called as
TASK_INTERRUPTIBLE. In the -rt patch, this code is commonly called when
PREEMPT_RT is enabled with TASK_UNINTERRUPTIBLE. But that's not the
likely scenario.
The rt_mutex() code should be optimized for the common vanilla case,
and that is from a futex, with TASK_INTERRUPTIBLE as the state.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20170119113234.1efeedd1@gandalf.local.home Signed-off-by: Ingo Molnar <mingo@kernel.org>
Waiman Long [Sun, 22 Jan 2017 02:33:35 +0000 (21:33 -0500)]
locking/rwsem: Reinit wake_q after use
In __rwsem_down_write_failed_common(), the same wake_q variable name
is defined twice, with the inner wake_q hiding the one in outer scope.
We can either use different names for the two wake_q's.
Even better, we can use the same wake_q twice, if necessary.
To enable the latter change, we need to define a new helper function
wake_q_init() to enable reinitalization of wake_q after use.
Signed-off-by: Waiman Long <longman@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1485052415-9611-1-git-send-email-longman@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Ingo Molnar [Sat, 14 Jan 2017 11:11:59 +0000 (12:11 +0100)]
locking/ww_mutex: Turn off __must_check for now
With the ww_mutex inline wrappers gone there's a lot of dormant
anti-patterns emerging in an x86 allyesconfig build:
kernel/locking/test-ww_mutex.c:80:2: warning: ignoring return value of ‘ww_mutex_lock’, declared with attribute warn_unused_result [-Wunused-result]
kernel/locking/test-ww_mutex.c:55:3: warning: ignoring return value of ‘ww_mutex_lock’, declared with attribute warn_unused_result [-Wunused-result]
kernel/locking/test-ww_mutex.c:134:2: warning: ignoring return value of ‘ww_mutex_lock’, declared with attribute warn_unused_result [-Wunused-result]
kernel/locking/test-ww_mutex.c:213:2: warning: ignoring return value of ‘ww_mutex_lock’, declared with attribute warn_unused_result [-Wunused-result]
kernel/locking/test-ww_mutex.c:177:2: warning: ignoring return value of ‘ww_mutex_lock’, declared with attribute warn_unused_result [-Wunused-result]
kernel/locking/test-ww_mutex.c:266:2: warning: ignoring return value of ‘ww_mutex_lock’, declared with attribute warn_unused_result [-Wunused-result]
lib/locking-selftest.c:213:19: warning: ignoring return value of ‘ww_mutex_lock’, declared with attribute warn_unused_result [-Wunused-result]
lib/locking-selftest.c:213:19: warning: ignoring return value of ‘ww_mutex_lock’, declared with attribute warn_unused_result [-Wunused-result]
lib/locking-selftest.c:213:19: warning: ignoring return value of ‘ww_mutex_lock’, declared with attribute warn_unused_result [-Wunused-result]
lib/locking-selftest.c:213:19: warning: ignoring return value of ‘ww_mutex_lock’, declared with attribute warn_unused_result [-Wunused-result]
lib/locking-selftest.c:213:19: warning: ignoring return value of ‘ww_mutex_lock’, declared with attribute warn_unused_result [-Wunused-result]
lib/locking-selftest.c:213:19: warning: ignoring return value of ‘ww_mutex_lock’, declared with attribute warn_unused_result [-Wunused-result]
lib/locking-selftest.c:213:19: warning: ignoring return value of ‘ww_mutex_lock’, declared with attribute warn_unused_result [-Wunused-result]
lib/locking-selftest.c:213:19: warning: ignoring return value of ‘ww_mutex_lock’, declared with attribute warn_unused_result [-Wunused-result]
lib/locking-selftest.c:211:20: warning: ignoring return value of ‘ww_mutex_lock’, declared with attribute warn_unused_result [-Wunused-result]
lib/locking-selftest.c:211:20: warning: ignoring return value of ‘ww_mutex_lock’, declared with attribute warn_unused_result [-Wunused-result]
lib/locking-selftest.c:211:20: warning: ignoring return value of ‘ww_mutex_lock’, declared with attribute warn_unused_result [-Wunused-result]
lib/locking-selftest.c:211:20: warning: ignoring return value of ‘ww_mutex_lock’, declared with attribute warn_unused_result [-Wunused-result]
lib/locking-selftest.c:213:19: warning: ignoring return value of ‘ww_mutex_lock’, declared with attribute warn_unused_result [-Wunused-result]
lib/locking-selftest.c:211:20: warning: ignoring return value of ‘ww_mutex_lock’, declared with attribute warn_unused_result [-Wunused-result]
lib/locking-selftest.c:211:20: warning: ignoring return value of ‘ww_mutex_lock’, declared with attribute warn_unused_result [-Wunused-result]
lib/locking-selftest.c:211:20: warning: ignoring return value of ‘ww_mutex_lock’, declared with attribute warn_unused_result [-Wunused-result]
drivers/gpu/drm/drm_modeset_lock.c:430:2: warning: ignoring return value of ‘ww_mutex_lock’, declared with attribute warn_unused_result [-Wunused-result]
drivers/gpu/drm/amd/amdgpu/amdgpu_prime.c:70:2: warning: ignoring return value of ‘ww_mutex_lock’, declared with attribute warn_unused_result [-Wunused-result]
drivers/gpu/drm/vgem/vgem_fence.c:193:2: warning: ignoring return value of ‘ww_mutex_lock’, declared with attribute warn_unused_result [-Wunused-result]
drivers/gpu/drm/i915/i915_gem_batch_pool.c:125:4: warning: ignoring return value of ‘ww_mutex_lock’, declared with attribute warn_unused_result [-Wunused-result]
drivers/gpu/drm/i915/i915_gem_execbuffer.c:1302:2: warning: ignoring return value of ‘ww_mutex_lock’, declared with attribute warn_unused_result [-Wunused-result]
drivers/gpu/drm/radeon/radeon_prime.c:69:2: warning: ignoring return value of ‘ww_mutex_lock’, declared with attribute warn_unused_result [-Wunused-result]
drivers/gpu/drm/nouveau/nouveau_prime.c:70:2: warning: ignoring return value of ‘ww_mutex_lock’, declared with attribute warn_unused_result [-Wunused-result]
... but we cannot just litter the kernel build log with such warnings.
These need to be fixed separately - turn off the warning for now.
Cc: Nicolai Hähnle <nicolai.haehnle@amd.com> Cc: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Daniel Vetter <daniel@ffwll.ch> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Maarten Lankhorst <dev@mblankhorst.nl> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: dri-devel@lists.freedesktop.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
Chris Wilson [Thu, 1 Dec 2016 11:47:11 +0000 (11:47 +0000)]
locking/ww_mutex: Add ww_mutex to tools/testing/selftests
Add the minimal test running (modprobe test-ww_mutex) to the kselftests
CI framework.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Shuah Khan <shuah@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20161201114711.28697-9-chris@chris-wilson.co.uk Signed-off-by: Ingo Molnar <mingo@kernel.org>
Chris Wilson [Thu, 1 Dec 2016 11:47:05 +0000 (11:47 +0000)]
locking/ww_mutex: Add ww_mutex to locktorture test
Although ww_mutexes degenerate into mutexes, it would be useful to
torture the deadlock handling between multiple ww_mutexes in addition to
torturing the regular mutexes.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Maarten Lankhorst <dev@mblankhorst.nl> Cc: Nicolai Hähnle <nhaehnle@gmail.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20161201114711.28697-3-chris@chris-wilson.co.uk Signed-off-by: Ingo Molnar <mingo@kernel.org>
Nicolai Hähnle [Wed, 21 Dec 2016 18:46:38 +0000 (19:46 +0100)]
locking/ww_mutex: Optimize ww-mutexes by yielding to other waiters from optimistic spin
Lock stealing is less beneficial for w/w mutexes since we may just end up
backing off if we stole from a thread with an earlier acquire stamp that
already holds another w/w mutex that we also need. So don't spin
optimistically unless we are sure that there is no other waiter that might
cause us to back off.
Median timings taken of a contention-heavy GPU workload:
Before:
real 0m52.946s
user 0m7.272s
sys 1m55.964s
After:
real 0m53.086s
user 0m7.360s
sys 1m46.204s
This particular workload still spends 20%-25% of CPU in mutex_spin_on_owner
according to perf, but my attempts to further reduce this spinning based on
various heuristics all lead to an increase in measured wall time despite
the decrease in sys time.
Signed-off-by: Nicolai Hähnle <Nicolai.Haehnle@amd.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Daniel Vetter <daniel@ffwll.ch> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Maarten Lankhorst <dev@mblankhorst.nl> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: dri-devel@lists.freedesktop.org Link: http://lkml.kernel.org/r/1482346000-9927-11-git-send-email-nhaehnle@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Nicolai Hähnle [Wed, 21 Dec 2016 18:46:37 +0000 (19:46 +0100)]
locking/ww_mutex: Re-check ww->ctx in the inner optimistic spin loop
In the following scenario, thread #1 should back off its attempt to lock
ww1 and unlock ww2 (assuming the acquire context stamps are ordered
accordingly).
Thread #0 Thread #1
--------- ---------
successfully lock ww2
set ww1->base.owner
attempt to lock ww1
confirm ww1->ctx == NULL
enter mutex_spin_on_owner
set ww1->ctx
What was likely to happen previously is:
attempt to lock ww2
refuse to spin because
ww2->ctx != NULL
schedule()
detect thread #0 is off CPU
stop optimistic spin
return -EDEADLK
unlock ww2
wakeup thread #0
lock ww2
... because thread #1 will stop its optimistic spin as soon as possible.
The whole scenario is quite unlikely, since it requires thread #1 to get
between thread #0 setting the owner and setting the ctx. But since we're
idling here anyway, the additional check is basically free.
Found by inspection.
Signed-off-by: Nicolai Hähnle <Nicolai.Haehnle@amd.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Daniel Vetter <daniel@ffwll.ch> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Maarten Lankhorst <dev@mblankhorst.nl> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: dri-devel@lists.freedesktop.org Link: http://lkml.kernel.org/r/1482346000-9927-10-git-send-email-nhaehnle@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Nicolai Hähnle [Wed, 21 Dec 2016 18:46:36 +0000 (19:46 +0100)]
locking/ww_mutex: Optimize ww-mutexes by waking at most one waiter for backoff when acquiring the lock
The wait list is sorted by stamp order, and the only waiting task that may
have to back off is the first waiter with a context.
The regular slow path does not have to wake any other tasks at all, since
all other waiters that would have to back off were either woken up when
the waiter was added to the list, or detected the condition before they
added themselves.
Median timings taken of a contention-heavy GPU workload:
Without this series:
real 0m59.900s
user 0m7.516s
sys 2m16.076s
With changes up to and including this patch:
real 0m52.946s
user 0m7.272s
sys 1m55.964s
Signed-off-by: Nicolai Hähnle <Nicolai.Haehnle@amd.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Daniel Vetter <daniel@ffwll.ch> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Maarten Lankhorst <dev@mblankhorst.nl> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: dri-devel@lists.freedesktop.org Link: http://lkml.kernel.org/r/1482346000-9927-9-git-send-email-nhaehnle@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Nicolai Hähnle [Wed, 21 Dec 2016 18:46:35 +0000 (19:46 +0100)]
locking/ww_mutex: Notify waiters that have to back off while adding tasks to wait list
While adding our task as a waiter, detect if another task should back off
because of us.
With this patch, we establish the invariant that the wait list contains
at most one (sleeping) waiter with ww_ctx->acquired > 0, and this waiter
will be the first waiter with a context.
Since only waiters with ww_ctx->acquired > 0 have to back off, this allows
us to be much more economical with wakeups.
Signed-off-by: Nicolai Hähnle <Nicolai.Haehnle@amd.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Daniel Vetter <daniel@ffwll.ch> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Maarten Lankhorst <dev@mblankhorst.nl> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: dri-devel@lists.freedesktop.org Link: http://lkml.kernel.org/r/1482346000-9927-8-git-send-email-nhaehnle@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Nicolai Hähnle [Wed, 21 Dec 2016 18:46:34 +0000 (19:46 +0100)]
locking/ww_mutex: Add waiters in stamp order
Add regular waiters in stamp order. Keep adding waiters that have no
context in FIFO order and take care not to starve them.
While adding our task as a waiter, back off if we detect that there is
a waiter with a lower stamp in front of us.
Make sure to call lock_contended even when we back off early.
For w/w mutexes, being first in the wait list is only stable when
taking the lock without a context. Therefore, the purpose of the first
flag is split into two: 'first' remains to indicate whether we want to
spin optimistically, while 'handoff' indicates that we should be
prepared to accept a handoff.
For w/w locking with a context, we always accept handoffs after the
first schedule(), to handle the following sequence of events:
1. Task #0 unlocks and hands off to Task #2 which is first in line
2. Task #1 adds itself in front of Task #2
3. Task #2 wakes up and must accept the handoff even though it is no
longer first in line
Signed-off-by: Nicolai Hähnle <nicolai.haehnle@amd.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: =?UTF-8?q?Nicolai=20H=C3=A4hnle?= <Nicolai.Haehnle@amd.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Daniel Vetter <daniel@ffwll.ch> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Maarten Lankhorst <dev@mblankhorst.nl> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: dri-devel@lists.freedesktop.org Link: http://lkml.kernel.org/r/1482346000-9927-7-git-send-email-nhaehnle@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Nicolai Hähnle [Wed, 21 Dec 2016 18:46:33 +0000 (19:46 +0100)]
locking/ww_mutex: Remove the __ww_mutex_lock*() inline wrappers
Keep the documentation in the header file since there is no good place
for it in mutex.c: there are two rather different implementations with
different EXPORT_SYMBOLs for each function.
Signed-off-by: Nicolai Hähnle <nicolai.haehnle@amd.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: =?UTF-8?q?Nicolai=20H=C3=A4hnle?= <Nicolai.Haehnle@amd.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Daniel Vetter <daniel@ffwll.ch> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Maarten Lankhorst <dev@mblankhorst.nl> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: dri-devel@lists.freedesktop.org Link: http://lkml.kernel.org/r/1482346000-9927-6-git-send-email-nhaehnle@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Nicolai Hähnle [Wed, 21 Dec 2016 18:46:32 +0000 (19:46 +0100)]
locking/ww_mutex: Set use_ww_ctx even when locking without a context
We will add a new field to struct mutex_waiter. This field must be
initialized for all waiters if any waiter uses the ww_use_ctx path.
So there is a trade-off: Keep ww_mutex locking without a context on
the faster non-use_ww_ctx path, at the cost of adding the
initialization to all mutex locks (including non-ww_mutexes), or avoid
the additional cost for non-ww_mutex locks, at the cost of adding
additional checks to the use_ww_ctx path.
We take the latter choice. It may be worth eliminating the users of
ww_mutex_lock(lock, NULL), but there are a lot of them.
Signed-off-by: Nicolai Hähnle <Nicolai.Haehnle@amd.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Daniel Vetter <daniel@ffwll.ch> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Maarten Lankhorst <dev@mblankhorst.nl> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: dri-devel@lists.freedesktop.org Link: http://lkml.kernel.org/r/1482346000-9927-5-git-send-email-nhaehnle@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Peter Zijlstra [Wed, 11 Jan 2017 13:17:48 +0000 (14:17 +0100)]
locking/mutex: Fix mutex handoff
While reviewing the ww_mutex patches, I noticed that it was still
possible to (incorrectly) succeed for (incorrect) code like:
mutex_lock(&a);
mutex_lock(&a);
This was possible if the second mutex_lock() would block (as expected)
but then receive a spurious wakeup. At that point it would find itself
at the front of the queue, request a handoff and instantly claim
ownership and continue, since owner would point to itself.
Avoid this scenario and simplify the code by introducing a third low
bit to signal handoff pickup. So once we request handoff, unlock
clears the handoff bit and sets the pickup bit along with the new
owner.
This also removes the need for the .handoff argument to
__mutex_trylock(), since that becomes superfluous with PICKUP.
In order to guarantee enough low bits, ensure task_struct alignment is
at least L1_CACHE_BYTES (which seems a good ideal regardless).
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Fixes: 9d659ae14b54 ("locking/mutex: Add lock handoff to avoid starvation") Signed-off-by: Ingo Molnar <mingo@kernel.org>
Davidlohr Bueso [Wed, 11 Jan 2017 15:22:26 +0000 (07:22 -0800)]
locking/percpu-rwsem: Replace waitqueue with rcuwait
The use of any kind of wait queue is an overkill for pcpu-rwsems.
While one option would be to use the less heavy simple (swait)
flavor, this is still too much for what pcpu-rwsems needs. For one,
we do not care about any sort of queuing in that the only (rare) time
writers (and readers, for that matter) are queued is when trying to
acquire the regular contended rw_sem. There cannot be any further
queuing as writers are serialized by the rw_sem in the first place.
Given that percpu_down_write() must not be called after exit_notify(),
we can replace the bulky waitqueue with rcuwait such that a writer
can wait for its turn to take the lock. As such, we can avoid the
queue handling and locking overhead.
Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Oleg Nesterov <oleg@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: dave@stgolabs.net Link: http://lkml.kernel.org/r/1484148146-14210-3-git-send-email-dave@stgolabs.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
Davidlohr Bueso [Wed, 11 Jan 2017 15:22:25 +0000 (07:22 -0800)]
sched/wait, RCU: Introduce rcuwait machinery
rcuwait provides support for (single) RCU-safe task wait/wake functionality,
with the caveat that it must not be called after exit_notify(), such that
we avoid racing with rcu delayed_put_task_struct callbacks, task_struct
being rcu unaware in this context -- for which we similarly have
task_rcu_dereference() magic, but with different return semantics, which
can conflict with the wakeup side.
The interfaces are quite straightforward:
rcuwait_wait_event()
rcuwait_wake_up()
More details are in the comments, but it's perhaps worth mentioning at least,
that users must provide proper serialization when waiting on a condition, and
avoid corrupting a concurrent waiter. Also care must be taken between the task
and the condition for when calling the wakeup -- we cannot miss wakeups. When
porting users, this is for example, a given when using waitqueues in that
everything is done under the q->lock. As such, it can remove sources of non
preemptable unbounded work for realtime.
Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Oleg Nesterov <oleg@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: dave@stgolabs.net Link: http://lkml.kernel.org/r/1484148146-14210-2-git-send-email-dave@stgolabs.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
Davidlohr Bueso [Tue, 3 Jan 2017 21:43:14 +0000 (13:43 -0800)]
sched/core: Remove set_task_state()
This is a nasty interface and setting the state of a foreign task must
not be done. As of the following commit:
be628be0956 ("bcache: Make gc wakeup sane, remove set_task_state()")
... everyone in the kernel calls set_task_state() with current, allowing
the helper to be removed.
However, as the comment indicates, it is still around for those archs
where computing current is more expensive than using a pointer, at least
in theory. An important arch that is affected is arm64, however this has
been addressed now [1] and performance is up to par making no difference
with either calls.
Of all the callers, if any, it's the locking bits that would care most
about this -- ie: we end up passing a tsk pointer to a lot of the lock
slowpath, and setting ->state on that. The following numbers are based
on two tests: a custom ad-hoc microbenchmark that just measures
latencies (for ~65 million calls) between get_task_state() vs
get_current_state().
Secondly for a higher overview, an unlink microbenchmark was used,
which pounds on a single file with open, close,unlink combos with
increasing thread counts (up to 4x ncpus). While the workload is quite
unrealistic, it does contend a lot on the inode mutex or now rwsem.
x86-64 (known to be fast for get_current()/this_cpu_read_stable() caching)
and ppc64 (with paca) show similar improvements in the unlink microbenches.
The small delta for ppc64 (2ms), does not represent the gains on the unlink
runs. In the case of x86, there was a decent amount of variation in the
latency runs, but always within a 20 to 50ms increase), ppc was more constant.
Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: dave@stgolabs.net Cc: mark.rutland@arm.com Link: http://lkml.kernel.org/r/1483479794-14013-5-git-send-email-dave@stgolabs.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
Davidlohr Bueso [Tue, 3 Jan 2017 21:43:13 +0000 (13:43 -0800)]
kernel/locking: Compute 'current' directly
This patch effectively replaces the tsk pointer dereference
(which is obviously == current), to directly use get_current()
macro. This is to make the removal of setting foreign task
states smoother and painfully obvious. Performance win on some
archs such as x86-64 and ppc64. On a microbenchmark that calls
set_task_state() vs set_current_state() and an inode rwsem
pounding benchmark doing unlink:
Davidlohr Bueso [Tue, 3 Jan 2017 21:43:12 +0000 (13:43 -0800)]
drivers/tty: Compute 'current' directly
This patch effectively replaces the tsk pointer dereference
(which is obviously == current), to directly use get_current()
macro. This is to make the removal of setting foreign task
states smoother and painfully obvious. Performance win on some
archs such as x86-64 and ppc64 -- arm64 is no longer an issue.
Signed-off-by: Davidlohr Bueso <dave@stgolabs.net> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: mark.rutland@arm.com Link: http://lkml.kernel.org/r/1483479794-14013-3-git-send-email-dave@stgolabs.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
Davidlohr Bueso [Tue, 3 Jan 2017 21:43:11 +0000 (13:43 -0800)]
kernel/exit: Compute 'current' directly
This patch effectively replaces the tsk pointer dereference (which is
obviously == current), to directly use get_current() macro. In this
case, do_exit() always passes current to exit_mm(), hence we can
simply get rid of the argument. This is also a performance win on some
archs such as x86-64 and ppc64 -- arm64 is no longer an issue.
Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: dave@stgolabs.net Cc: mark.rutland@arm.com Link: http://lkml.kernel.org/r/1483479794-14013-2-git-send-email-dave@stgolabs.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
Linus Torvalds [Wed, 11 Jan 2017 19:15:15 +0000 (11:15 -0800)]
Merge branch 'akpm' (patches from Andrew)
Merge fixes from Andrew Morton:
"27 fixes.
There are three patches that aren't actually fixes. They're simple
function renamings which are nice-to-have in mainline as ongoing net
development depends on them."
* akpm: (27 commits)
timerfd: export defines to userspace
mm/hugetlb.c: fix reservation race when freeing surplus pages
mm/slab.c: fix SLAB freelist randomization duplicate entries
zram: support BDI_CAP_STABLE_WRITES
zram: revalidate disk under init_lock
mm: support anonymous stable page
mm: add documentation for page fragment APIs
mm: rename __page_frag functions to __page_frag_cache, drop order from drain
mm: rename __alloc_page_frag to page_frag_alloc and __free_page_frag to page_frag_free
mm, memcg: fix the active list aging for lowmem requests when memcg is enabled
mm: don't dereference struct page fields of invalid pages
mailmap: add codeaurora.org names for nameless email commits
signal: protect SIGNAL_UNKILLABLE from unintentional clearing.
mm: pmd dirty emulation in page fault handler
ipc/sem.c: fix incorrect sem_lock pairing
lib/Kconfig.debug: fix frv build failure
mm: get rid of __GFP_OTHER_NODE
mm: fix remote numa hits statistics
mm: fix devm_memremap_pages crash, use mem_hotplug_{begin, done}
ocfs2: fix crash caused by stale lvb with fsdlm plugin
...
2) Memory disclosure in appletalk ipddp routing code, from Vlad
Tsyrklevich.
3) r8152 can erroneously split an RX packet into multiple URBs if the
Rx FIFO is not empty when we suspend. Fix this by waiting for the
FIFO to empty before suspending. From Hayes Wang.
4) Two GRO fixes (enter slow path when not enough SKB tail room exists,
disable frag0 optimizations when there are IPV6 extension headers)
from Eric Dumazet and Herbert Xu.
5) A series of mlx5e bug fixes (do source udp port offloading for
tunnels properly, Ip fragment matching fixes, handling firmware
errors properly when installing TC rules, etc.) from Saeed Mahameed,
Or Gerlitz, Roi Dayan, Hadar Hen Zion, Gil Rockah, and Daniel
Jurgens.
6) Two VRF fixes from David Ahern (don't skip multipath selection for
VRF paths, disallow VRF to be configured with table ID 0).
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (35 commits)
net: vrf: do not allow table id 0
net: phy: marvell: fix Marvell 88E1512 used in SGMII mode
sctp: Fix spelling mistake: "Atempt" -> "Attempt"
net: ipv4: Fix multipath selection with vrf
cgroup: move CONFIG_SOCK_CGROUP_DATA to init/Kconfig
gro: use min_t() in skb_gro_reset_offset()
net/mlx5: Only cancel recovery work when cleaning up device
net/mlx5e: Remove WARN_ONCE from adaptive moderation code
net/mlx5e: Un-register uplink representor on nic_disable
net/mlx5e: Properly handle FW errors while adding TC rules
net/mlx5e: Fix kbuild warnings for uninitialized parameters
net/mlx5e: Set inline mode requirements for matching on IP fragments
net/mlx5e: Properly get address type of encapsulation IP headers
net/mlx5e: TC ipv4 tunnel encap offload error flow fixes
net/mlx5e: Warn when rejecting offload attempts of IP tunnels
net/mlx5e: Properly handle offloading of source udp port for IP tunnels
gro: Disable frag0 optimization on IPv6 ext headers
gro: Enter slow-path if there is no tailroom
mlx4: Return EOPNOTSUPP instead of ENOTSUPP
net/af_iucv: don't use paged skbs for TX on HiperSockets
...
David Ahern [Tue, 10 Jan 2017 23:22:25 +0000 (15:22 -0800)]
net: vrf: do not allow table id 0
Frank reported that vrf devices can be created with a table id of 0.
This breaks many of the run time table id checks and should not be
allowed. Detect this condition at create time and fail with EINVAL.
Fixes: 193125dbd8eb ("net: Introduce VRF device driver") Reported-by: Frank Kellermann <frank.kellermann@atos.net> Signed-off-by: David Ahern <dsa@cumulusnetworks.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Russell King [Tue, 10 Jan 2017 23:13:45 +0000 (23:13 +0000)]
net: phy: marvell: fix Marvell 88E1512 used in SGMII mode
When an Marvell 88E1512 PHY is connected to a nic in SGMII mode, the
fiber page is used for the SGMII host-side connection. The PHY driver
notices that SUPPORTED_FIBRE is set, so it tries reading the fiber page
for the link status, and ends up reading the MAC-side status instead of
the outgoing (copper) link. This leads to incorrect results reported
via ethtool.
If the PHY is connected via SGMII to the host, ignore the fiber page.
However, continue to allow the existing power management code to
suspend and resume the fiber page.
Fixes: 6cfb3bcc0641 ("Marvell phy: check link status in case of fiber link.") Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk> Signed-off-by: David S. Miller <davem@davemloft.net>
Colin Ian King [Tue, 10 Jan 2017 22:53:06 +0000 (22:53 +0000)]
sctp: Fix spelling mistake: "Atempt" -> "Attempt"
Trivial fix to spelling mistake in WARN_ONCE message
Signed-off-by: Colin Ian King <colin.king@canonical.com> Acked-by: Neil Horman <nhorman@tuxdriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
David Ahern [Tue, 10 Jan 2017 22:37:35 +0000 (14:37 -0800)]
net: ipv4: Fix multipath selection with vrf
fib_select_path does not call fib_select_multipath if oif is set in the
flow struct. For VRF use cases oif is always set, so multipath route
selection is bypassed. Use the FLOWI_FLAG_SKIP_NH_OIF to skip the oif
check similar to what is done in fib_table_lookup.
Add saddr and proto to the flow struct for the fib lookup done by the
VRF driver to better match hash computation for a flow.
Fixes: 613d09b30f8b ("net: Use VRF device index for lookups on TX") Signed-off-by: David Ahern <dsa@cumulusnetworks.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Arnd Bergmann [Tue, 10 Jan 2017 12:08:06 +0000 (13:08 +0100)]
cgroup: move CONFIG_SOCK_CGROUP_DATA to init/Kconfig
We now 'select SOCK_CGROUP_DATA' but Kconfig complains that this is
not right when CONFIG_NET is disabled and there is no socket interface:
warning: (CGROUP_BPF) selects SOCK_CGROUP_DATA which has unmet direct dependencies (NET)
I don't know what the correct solution for this is, but simply removing
the dependency on NET from SOCK_CGROUP_DATA by moving it out of the
'if NET' section avoids the warning and does not produce other build
errors.
Fixes: 483c4933ea09 ("cgroup: Fix CGROUP_BPF config") Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: David S. Miller <davem@davemloft.net>
Eric Dumazet [Wed, 11 Jan 2017 03:52:43 +0000 (19:52 -0800)]
gro: use min_t() in skb_gro_reset_offset()
On 32bit arches, (skb->end - skb->data) is not 'unsigned int',
so we shall use min_t() instead of min() to avoid a compiler error.
Fixes: 1272ce87fa01 ("gro: Enter slow-path if there is no tailroom") Reported-by: kernel test robot <fengguang.wu@intel.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
David S. Miller [Wed, 11 Jan 2017 02:34:03 +0000 (21:34 -0500)]
Merge branch 'mlx5-fixes'
Saeed Mahameed says:
====================
Mellanox mlx5 fixes and cleanups 2017-01-10
This series includes some mlx5e general cleanups from Daniel, Gil, Hadar
and myself.
Also it includes some critical mlx5e TC offloads fixes from Or Gerlitz.
For -stable:
- net/mlx5e: Remove WARN_ONCE from adaptive moderation code
Although this fix doesn't affect any functionality, I thought it is
better to clean this -WARN_ONCE- up for -stable in case someone hits
such corner case.
Please apply and let me know if there's any problem.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
Daniel Jurgens [Tue, 10 Jan 2017 20:33:39 +0000 (22:33 +0200)]
net/mlx5: Only cancel recovery work when cleaning up device
Do not attempt to drain the health workqueue when unloading the device in
the recovery flow, this can cause a deadlock when the recovery work
tries to cancel itself with sync.
Because the work is no longer unconditionally canceled when unloading, it
must be explicitly canceled in the AER flow.
fixes: 689a248df83b ("net/mlx5: Cancel recovery work in remove flow") Signed-off-by: Daniel Jurgens <danielj@mellanox.com> Signed-off-by: Saeed Mahameed <saeedm@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Gil Rockah [Tue, 10 Jan 2017 20:33:38 +0000 (22:33 +0200)]
net/mlx5e: Remove WARN_ONCE from adaptive moderation code
When trying to do interface down or changing interface configuration
under heavy traffic, some of the adaptive moderation corner cases can
occur and leave a WARN_ONCE call trace in the kernel log.
Those WARN_ONCE are meant for debug only, and should have been inserted
only under debug. We avoid such call traces by removing those WARN_ONCE.
Fixes: cb3c7fd4f839 ("net/mlx5e: Support adaptive RX coalescing") Signed-off-by: Gil Rockah <gilr@mellanox.com> Signed-off-by: Saeed Mahameed <saeedm@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Saeed Mahameed [Tue, 10 Jan 2017 20:33:37 +0000 (22:33 +0200)]
net/mlx5e: Un-register uplink representor on nic_disable
The code before this patch registered uplink e-Switch representor
on nic_enable and unregistered on nic_cleanup, the right place
for this unregister is in nic_disable.
Fixes: 127ea380acc9 ("net/mlx5: Add Representors registration API") Signed-off-by: Saeed Mahameed <saeedm@mellanox.com> Reviewed-by: Mohamad Haj Yahia <mohamad@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Or Gerlitz [Tue, 10 Jan 2017 20:33:36 +0000 (22:33 +0200)]
net/mlx5e: Properly handle FW errors while adding TC rules
When the firmware returns an error (common example is an attempt to
add twice the same rule which is refused by the some FWs), we are not
properly derefing/cleaning few resources allocated on the way.
Examples are vport vlan deref under eswitch vlan offloads, and encap
entry/neighbour deref under eswitch encapsulation offloads, fix that.
Fixes: a54e20b4fcae ('net/mlx5e: Add basic TC tunnel set action for SRIOV offloads') Fixes: 8b32580df1cb ('net/mlx5e: Add TC vlan action for SRIOV offloads') Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com> Reviewed-by: Roi Dayan <roid@mellanox.com> Signed-off-by: Saeed Mahameed <saeedm@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Hadar Hen Zion [Tue, 10 Jan 2017 20:33:35 +0000 (22:33 +0200)]
net/mlx5e: Fix kbuild warnings for uninitialized parameters
kbuild warn about parameters that may be used uninitialized, fix it.
Fixes: a54e20b4fcae ('net/mlx5e: Add basic TC tunnel set action for SRIOV offloads') Signed-off-by: Hadar Hen Zion <hadarh@mellanox.com> Signed-off-by: Saeed Mahameed <saeedm@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Or Gerlitz [Tue, 10 Jan 2017 20:33:34 +0000 (22:33 +0200)]
net/mlx5e: Set inline mode requirements for matching on IP fragments
For e-switch level matching on packets being an IP fragment, we
need to make sure the source vport inline mode is L3, fix that.
Fixes: 3f7d0eb42d59 ('net/mlx5e: Offload TC matching on packets being IP fragments') Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com> Reviewed-by: Roi Dayan <roid@mellanox.com> Signed-off-by: Saeed Mahameed <saeedm@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Or Gerlitz [Tue, 10 Jan 2017 20:33:33 +0000 (22:33 +0200)]
net/mlx5e: Properly get address type of encapsulation IP headers
As done elsewhere in our TC/flower offload code, the address type of
the encapsulation IP headers should be realized accroding to the
addr_type field of the encapsulation control dissector key, do that.
Fixes: bbd00f7e2349 ('net/mlx5e: Add TC tunnel release action for SRIOV offloads') Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com> Reviewed-by: Hadar Hen Zion <hadarh@mellanox.com> Signed-off-by: Saeed Mahameed <saeedm@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
When the route lookup fails we should return the actual error.
When the neigh isn't valid, we should return -EOPNOTSUPP as done
in similar cases along the code.
When the offload can't take place as of invalid neigh etc, we
must release the neigh.
Fixes: a54e20b4fcae ('net/mlx5e: Add basic TC tunnel set action for SRIOV offloads') Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com> Reviewed-by: Hadar Hen Zion <hadarh@mellanox.com> Signed-off-by: Saeed Mahameed <saeedm@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Or Gerlitz [Tue, 10 Jan 2017 20:33:31 +0000 (22:33 +0200)]
net/mlx5e: Warn when rejecting offload attempts of IP tunnels
We silently reject offloading of IPv6 tunnels, non vxlan tunnels,
vxlan tunnels where the dst port to match is not provided, etc.
Be a bit more verbose and print a warning so the user better
realizes what went wrong here and can fix it.
Fixes: a54e20b4fcae ('net/mlx5e: Add basic TC tunnel set action for SRIOV offloads') Fixes: bbd00f7e2349 ('net/mlx5e: Add TC tunnel release action for SRIOV offloads') Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com> Reviewed-by: Hadar Hen Zion <hadarh@mellanox.com> Signed-off-by: Saeed Mahameed <saeedm@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Or Gerlitz [Tue, 10 Jan 2017 20:33:30 +0000 (22:33 +0200)]
net/mlx5e: Properly handle offloading of source udp port for IP tunnels
We can offload the matching on source udp port of ip tunnels for
decapsulation. We can not offload setting source udp port for tunnels
as part of encapsulation. Fix both the code that deals with matching
offload (decap) and the code that deal with encap offload to align with
that.
Fixes: a54e20b4fcae ('net/mlx5e: Add basic TC tunnel set action for SRIOV offloads') Fixes: bbd00f7e2349 ('net/mlx5e: Add TC tunnel release action for SRIOV offloads') Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com> Reviewed-by: Hadar Hen Zion <hadarh@mellanox.com> Signed-off-by: Saeed Mahameed <saeedm@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Mike Frysinger [Wed, 11 Jan 2017 00:58:30 +0000 (16:58 -0800)]
timerfd: export defines to userspace
Since userspace is expected to call timerfd syscalls directly with these
flags/ioctls, make sure we export them so they don't have to duplicate
the values themselves.
Link: http://lkml.kernel.org/r/20161219064052.7196-1-vapier@gentoo.org Signed-off-by: Mike Frysinger <vapier@gentoo.org> Acked-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Mike Kravetz [Wed, 11 Jan 2017 00:58:27 +0000 (16:58 -0800)]
mm/hugetlb.c: fix reservation race when freeing surplus pages
return_unused_surplus_pages() decrements the global reservation count,
and frees any unused surplus pages that were backing the reservation.
Commit 7848a4bf51b3 ("mm/hugetlb.c: add cond_resched_lock() in
return_unused_surplus_pages()") added a call to cond_resched_lock in the
loop freeing the pages.
As a result, the hugetlb_lock could be dropped, and someone else could
use the pages that will be freed in subsequent iterations of the loop.
This could result in inconsistent global hugetlb page state, application
api failures (such as mmap) failures or application crashes.
When dropping the lock in return_unused_surplus_pages, make sure that
the global reservation count (resv_huge_pages) remains sufficiently
large to prevent someone else from claiming pages about to be freed.
Analyzed by Paul Cassella.
Fixes: 7848a4bf51b3 ("mm/hugetlb.c: add cond_resched_lock() in return_unused_surplus_pages()") Link: http://lkml.kernel.org/r/1483991767-6879-1-git-send-email-mike.kravetz@oracle.com Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> Reported-by: Paul Cassella <cassella@cray.com> Suggested-by: Michal Hocko <mhocko@kernel.org> Cc: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com> Cc: Hillf Danton <hillf.zj@alibaba-inc.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>
This patch fixes a bug in the freelist randomization code. When a high
random number is used, the freelist will contain duplicate entries. It
will result in different allocations sharing the same chunk.
It will result in odd behaviours and crashes. It should be uncommon but
it depends on the machines. We saw it happening more often on some
machines (every few hours of running tests).
Fixes: c7ce4f60ac19 ("mm: SLAB freelist randomization") Link: http://lkml.kernel.org/r/20170103181908.143178-1-thgarnie@google.com Signed-off-by: John Sperbeck <jsperbeck@google.com> Signed-off-by: Thomas Garnier <thgarnie@google.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Minchan Kim [Wed, 11 Jan 2017 00:58:21 +0000 (16:58 -0800)]
zram: support BDI_CAP_STABLE_WRITES
zram has used per-cpu stream feature from v4.7. It aims for increasing
cache hit ratio of scratch buffer for compressing. Downside of that
approach is that zram should ask memory space for compressed page in
per-cpu context which requires stricted gfp flag which could be failed.
If so, it retries to allocate memory space out of per-cpu context so it
could get memory this time and compress the data again, copies it to the
memory space.
In this scenario, zram assumes the data should never be changed but it is
not true without stable page support. So, If the data is changed under
us, zram can make buffer overrun so that zsmalloc free object chain is
broken so system goes crash like below
https://bugzilla.suse.com/show_bug.cgi?id=997574
This patch adds BDI_CAP_STABLE_WRITES to zram for declaring "I am block
device needing *stable write*".
Fixes: da9556a2367c ("zram: user per-cpu compression streams") Link: http://lkml.kernel.org/r/1482366980-3782-4-git-send-email-minchan@kernel.org Signed-off-by: Minchan Kim <minchan@kernel.org> Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Takashi Iwai <tiwai@suse.de> Cc: Hyeoncheol Lee <cheol.lee@lge.com> Cc: <yjay.kim@lge.com> Cc: Sangseok Lee <sangseok.lee@lge.com> Cc: Hugh Dickins <hughd@google.com> Cc: Darrick J. Wong <darrick.wong@oracle.com> Cc: <stable@vger.kernel.org> [4.7+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Minchan Kim [Wed, 11 Jan 2017 00:58:18 +0000 (16:58 -0800)]
zram: revalidate disk under init_lock
Commit b4c5c60920e3 ("zram: avoid lockdep splat by revalidate_disk")
moved revalidate_disk call out of init_lock to avoid lockdep
false-positive splat. However, commit 08eee69fcf6b ("zram: remove
init_lock in zram_make_request") removed init_lock in IO path so there
is no worry about lockdep splat. So, let's restore it.
This patch is needed to set BDI_CAP_STABLE_WRITES atomically in next
patch.
Fixes: da9556a2367c ("zram: user per-cpu compression streams") Link: http://lkml.kernel.org/r/1482366980-3782-3-git-send-email-minchan@kernel.org Signed-off-by: Minchan Kim <minchan@kernel.org> Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Takashi Iwai <tiwai@suse.de> Cc: Hyeoncheol Lee <cheol.lee@lge.com> Cc: <yjay.kim@lge.com> Cc: Sangseok Lee <sangseok.lee@lge.com> Cc: Hugh Dickins <hughd@google.com> Cc: Darrick J. Wong <darrick.wong@oracle.com> Cc: <stable@vger.kernel.org> [4.7+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
With investigation, it reveals currently stable page doesn't support
anonymous page. IOW, reuse_swap_page can reuse the page without waiting
writeback completion so it can overwrite page zram is compressing.
Unfortunately, zram has used per-cpu stream feature from v4.7.
It aims for increasing cache hit ratio of scratch buffer for
compressing. Downside of that approach is that zram should ask
memory space for compressed page in per-cpu context which requires
stricted gfp flag which could be failed. If so, it retries to
allocate memory space out of per-cpu context so it could get memory
this time and compress the data again, copies it to the memory space.
In this scenario, zram assumes the data should never be changed
but it is not true unless stable page supports. So, If the data is
changed under us, zram can make buffer overrun because second
compression size could be bigger than one we got in previous trial
and blindly, copy bigger size object to smaller buffer which is
buffer overrun. The overrun breaks zsmalloc free object chaining
so system goes crash like above.
I think below is same problem.
https://bugzilla.suse.com/show_bug.cgi?id=997574
Unfortunately, reuse_swap_page should be atomic so that we cannot wait on
writeback in there so the approach in this patch is simply return false if
we found it needs stable page. Although it increases memory footprint
temporarily, it happens rarely and it should be reclaimed easily althoug
it happened. Also, It would be better than waiting of IO completion,
which is critial path for application latency.
Fixes: da9556a2367c ("zram: user per-cpu compression streams") Link: http://lkml.kernel.org/r/20161120233015.GA14113@bbox Link: http://lkml.kernel.org/r/1482366980-3782-2-git-send-email-minchan@kernel.org Signed-off-by: Minchan Kim <minchan@kernel.org> Acked-by: Hugh Dickins <hughd@google.com> Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Darrick J. Wong <darrick.wong@oracle.com> Cc: Takashi Iwai <tiwai@suse.de> Cc: Hyeoncheol Lee <cheol.lee@lge.com> Cc: <yjay.kim@lge.com> Cc: Sangseok Lee <sangseok.lee@lge.com> Cc: <stable@vger.kernel.org> [4.7+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Alexander Duyck [Wed, 11 Jan 2017 00:58:12 +0000 (16:58 -0800)]
mm: add documentation for page fragment APIs
This is a first pass at trying to add documentation for the page_frag
APIs. They may still change over time but for now I thought I would try
to get these documented so that as more network drivers and stack calls
make use of them we have one central spot to document how they are meant
to be used.
Alexander Duyck [Wed, 11 Jan 2017 00:58:09 +0000 (16:58 -0800)]
mm: rename __page_frag functions to __page_frag_cache, drop order from drain
This patch does two things.
First it goes through and renames the __page_frag prefixed functions to
__page_frag_cache so that we can be clear that we are draining or
refilling the cache, not the frags themselves.
Second we drop the order parameter from __page_frag_cache_drain since we
don't actually need to pass it since all fragments are either order 0 or
must be a compound page.
Alexander Duyck [Wed, 11 Jan 2017 00:58:06 +0000 (16:58 -0800)]
mm: rename __alloc_page_frag to page_frag_alloc and __free_page_frag to page_frag_free
Patch series "Page fragment updates", v4.
This patch series takes care of a few cleanups for the page fragments
API.
First we do some renames so that things are much more consistent. First
we move the page_frag_ portion of the name to the front of the functions
names. Secondly we split out the cache specific functions from the
other page fragment functions by adding the word "cache" to the name.
Finally I added a bit of documentation that will hopefully help to
explain some of this. I plan to revisit this later as we get things
more ironed out in the near future with the changes planned for the DMA
setup to support eXpress Data Path.
This patch (of 3):
This patch renames the page frag functions to be more consistent with
other APIs. Specifically we place the name page_frag first in the name
and then have either an alloc or free call name that we append as the
suffix. This makes it a bit clearer in terms of naming.
In addition we drop the leading double underscores since we are
technically no longer a backing interface and instead the front end that
is called from the networking APIs.
the oom killer is clearly pre-mature because there there is still a lot
of page cache in the zone Normal which should satisfy this lowmem
request. Further debugging has shown that the reclaim cannot make any
forward progress because the page cache is hidden in the active list
which doesn't get rotated because inactive_list_is_low is not memcg
aware.
The code simply subtracts per-zone highmem counters from the respective
memcg's lru sizes which doesn't make any sense. We can simply end up
always seeing the resulting active and inactive counts 0 and return
false. This issue is not limited to 32b kernels but in practice the
effect on systems without CONFIG_HIGHMEM would be much harder to notice
because we do not invoke the OOM killer for allocations requests
targeting < ZONE_NORMAL.
Fix the issue by tracking per zone lru page counts in mem_cgroup_per_node
and subtract per-memcg highmem counts when memcg is enabled. Introduce
helper lruvec_zone_lru_size which redirects to either zone counters or
mem_cgroup_get_zone_lru_size when appropriate.
We are losing empty LRU but non-zero lru size detection introduced by ca707239e8a7 ("mm: update_lru_size warn and reset bad lru_size") because
of the inherent zone vs. node discrepancy.
Fixes: f8d1a31163fc ("mm: consider whether to decivate based on eligible zones inactive ratio") Link: http://lkml.kernel.org/r/20170104100825.3729-1-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Reported-by: Nils Holland <nholland@tisys.org> Tested-by: Nils Holland <nholland@tisys.org> Reported-by: Klaus Ethgen <Klaus@Ethgen.de> Acked-by: Minchan Kim <minchan@kernel.org> Acked-by: Mel Gorman <mgorman@suse.de> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: <stable@vger.kernel.org> [4.8+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Ard Biesheuvel [Wed, 11 Jan 2017 00:58:00 +0000 (16:58 -0800)]
mm: don't dereference struct page fields of invalid pages
The VM_BUG_ON() check in move_freepages() checks whether the node id of
a page matches the node id of its zone. However, it does this before
having checked whether the struct page pointer refers to a valid struct
page to begin with. This is guaranteed in most cases, but may not be
the case if CONFIG_HOLES_IN_ZONE=y.
So reorder the VM_BUG_ON() with the pfn_valid_within() check.
Link: http://lkml.kernel.org/r/1481706707-6211-2-git-send-email-ard.biesheuvel@linaro.org Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Acked-by: Will Deacon <will.deacon@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Hanjun Guo <hanjun.guo@linaro.org> Cc: Yisheng Xie <xieyisheng1@huawei.com> Cc: Robert Richter <rrichter@cavium.com> Cc: James Morse <james.morse@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Jamie Iles [Wed, 11 Jan 2017 00:57:54 +0000 (16:57 -0800)]
signal: protect SIGNAL_UNKILLABLE from unintentional clearing.
Since commit 00cd5c37afd5 ("ptrace: permit ptracing of /sbin/init") we
can now trace init processes. init is initially protected with
SIGNAL_UNKILLABLE which will prevent fatal signals such as SIGSTOP, but
there are a number of paths during tracing where SIGNAL_UNKILLABLE can
be implicitly cleared.
This can result in init becoming stoppable/killable after tracing. For
example, running:
while true; do kill -STOP 1; done &
strace -p 1
and then stopping strace and the kill loop will result in init being
left in state TASK_STOPPED. Sending SIGCONT to init will resume it, but
init will now respond to future SIGSTOP signals rather than ignoring
them.
Make sure that when setting SIGNAL_STOP_CONTINUED/SIGNAL_STOP_STOPPED
that we don't clear SIGNAL_UNKILLABLE.
Link: http://lkml.kernel.org/r/20170104122017.25047-1-jamie.iles@oracle.com Signed-off-by: Jamie Iles <jamie.iles@oracle.com> Acked-by: Oleg Nesterov <oleg@redhat.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The problem is currently page fault handler doesn't supports dirty bit
emulation of pmd for non-HW dirty-bit architecture so that application
stucks until VM marked the pmd dirty.
How the emulation work depends on the architecture. In case of arm64,
when it set up pte firstly, it sets pte PTE_RDONLY to get a chance to
mark the pte dirty via triggering page fault when store access happens.
Once the page fault occurs, VM marks the pmd dirty and arch code for
setting pmd will clear PTE_RDONLY for application to proceed.
IOW, if VM doesn't mark the pmd dirty, application hangs forever by
repeated fault(i.e., store op but the pmd is PTE_RDONLY).
This patch enables pmd dirty-bit emulation for those architectures.
[1] b8d3c4c3009d, mm/huge_memory.c: don't split THP page when MADV_FREE syscall is called
Fixes: b8d3c4c3009d ("mm/huge_memory.c: don't split THP page when MADV_FREE syscall is called") Link: http://lkml.kernel.org/r/1482506098-6149-1-git-send-email-minchan@kernel.org Signed-off-by: Minchan Kim <minchan@kernel.org> Reported-by: Andreas Schwab <schwab@suse.de> Tested-by: Andreas Schwab <schwab@suse.de> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Jason Evans <je@fb.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: <stable@vger.kernel.org> [4.5+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The slow (i.e.: failure to acquire) syscall exit from semtimedop()
incorrectly assumed that the the same lock is acquired as it was at the
initial syscall entry.
This is wrong:
- thread A: single semop semop(), sleeps
- thread B: multi semop semop(), sleeps
- thread A: woken up by signal/timeout
With this sequence, the initial sem_lock() call locks the per-semaphore
spinlock, and it is unlocked with sem_unlock(). The call at the syscall
return locks the global spinlock. Because locknum is not updated, the
following sem_unlock() call unlocks the per-semaphore spinlock, which is
actually not locked.
The fix is trivial: Use the return value from sem_lock.
Fixes: 370b262c896e ("ipc/sem: avoid idr tree lookup for interrupted semop") Link: http://lkml.kernel.org/r/1482215645-22328-1-git-send-email-manfred@colorfullife.com Signed-off-by: Manfred Spraul <manfred@colorfullife.com> Reported-by: Dmitry Vyukov <dvyukov@google.com> Reported-by: Johanna Abrahamsson <johanna@mjao.org> Tested-by: Johanna Abrahamsson <johanna@mjao.org> Acked-by: Davidlohr Bueso <dave@stgolabs.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Sudip Mukherjee [Wed, 11 Jan 2017 00:57:45 +0000 (16:57 -0800)]
lib/Kconfig.debug: fix frv build failure
The build of frv allmodconfig was failing with the errors like:
/tmp/cc0JSPc3.s: Assembler messages:
/tmp/cc0JSPc3.s:1839: Error: symbol `.LSLT0' is already defined
/tmp/cc0JSPc3.s:1842: Error: symbol `.LASLTP0' is already defined
/tmp/cc0JSPc3.s:1969: Error: symbol `.LELTP0' is already defined
/tmp/cc0JSPc3.s:1970: Error: symbol `.LELT0' is already defined
Commit 866ced950bcd ("kbuild: Support split debug info v4") introduced
splitting the debug info and keeping that in a separate file. Somehow,
the frv-linux gcc did not like that and I am guessing that instead of
splitting it started copying. The first report about this is at:
I will try and see if this can work with frv and if still fails I will
open a bug report with gcc. But meanwhile this is the easiest option to
solve build failure of frv.
Fixes: 866ced950bcd ("kbuild: Support split debug info v4") Link: http://lkml.kernel.org/r/1482062348-5352-1-git-send-email-sudipm.mukherjee@gmail.com Signed-off-by: Sudip Mukherjee <sudip.mukherjee@codethink.co.uk> Reported-by: Fengguang Wu <fengguang.wu@intel.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Michal Hocko [Wed, 11 Jan 2017 00:57:42 +0000 (16:57 -0800)]
mm: get rid of __GFP_OTHER_NODE
The flag was introduced by commit 78afd5612deb ("mm: add
__GFP_OTHER_NODE flag") to allow proper accounting of remote node
allocations done by kernel daemons on behalf of a process - e.g.
khugepaged.
After "mm: fix remote numa hits statistics" we do not need and actually
use the flag so we can safely remove it because all allocations which
are satisfied from their "home" node are accounted properly.
[mhocko@suse.com: fix build] Link: http://lkml.kernel.org/r/20170106122225.GK5556@dhcp22.suse.cz Link: http://lkml.kernel.org/r/20170102153057.9451-3-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Acked-by: Mel Gorman <mgorman@suse.de> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Michal Hocko <mhocko@suse.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Taku Izumi <izumi.taku@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Michal Hocko [Wed, 11 Jan 2017 00:57:39 +0000 (16:57 -0800)]
mm: fix remote numa hits statistics
Jia He has noticed that commit b9f00e147f27 ("mm, page_alloc: reduce
branches in zone_statistics") has an unintentional side effect that
remote node allocation requests are accounted as NUMA_MISS rathat than
NUMA_HIT and NUMA_OTHER if such a request doesn't use __GFP_OTHER_NODE.
There are many of these potentially because the flag is used very rarely
while we have many users of __alloc_pages_node.
Fix this by simply ignoring __GFP_OTHER_NODE (it can be removed in a
follow up patch) and treat all allocations that were satisfied from the
preferred zone's node as NUMA_HITS because this is the same node we
requested the allocation from in most cases. If this is not the local
node then we just account it as NUMA_OTHER rather than NUMA_LOCAL.
One downsize would be that an allocation request for a node which is
outside of the mempolicy nodemask would be reported as a hit which is a
bit weird but that was the case before b9f00e147f27 already.
Fixes: b9f00e147f27 ("mm, page_alloc: reduce branches in zone_statistics") Link: http://lkml.kernel.org/r/20170102153057.9451-2-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Reported-by: Jia He <hejianet@gmail.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> # with cbmc[1] superpowers Acked-by: Mel Gorman <mgorman@suse.de> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Taku Izumi <izumi.taku@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The result is that two threads calling devm_memremap_pages()
simultaneously can end up colliding on pgd initialization. This leads
to crash signatures like the following where the loser of the race
initializes the wrong pgd entry:
It's because ocfs2_inode_lock() get us stale LVB in which the i_size is
not equal to the disk i_size. We mistakenly trust the LVB because the
underlaying fsdlm dlm_lock() doesn't set lkb_sbflags with
DLM_SBF_VALNOTVALID properly for us. But, why?
The current code tries to downconvert lock without DLM_LKF_VALBLK flag
to tell o2cb don't update RSB's LVB if it's a PR->NULL conversion, even
if the lock resource type needs LVB. This is not the right way for
fsdlm.
The fsdlm plugin behaves different on DLM_LKF_VALBLK, it depends on
DLM_LKF_VALBLK to decide if we care about the LVB in the LKB. If
DLM_LKF_VALBLK is not set, fsdlm will skip recovering RSB's LVB from
this lkb and set the right DLM_SBF_VALNOTVALID appropriately when node
failure happens.
The following diagram briefly illustrates how this crash happens:
RSB1 is inode metadata lock resource with LOCK_TYPE_USES_LVB;
dlm_lock(no DLM_LKF_VALBLK)
convert_lock(overwrite lkb->lkb_exflags
with no DLM_LKF_VALBLK)
RSB1: NULL RSB1: EX
reset Node2
dlm_recover_rsbs()
recover_lvb()
/* The LVB is not trustable if the node with EX fails and
* no lock >= PR is left. We should set RSB_VALNOTVALID for RSB1.
*/
if(!(kb_exflags & DLM_LKF_VALBLK)) /* This means we miss the chance to
return; * to invalid the LVB here.
*/
The 2nd round:
Node 1 Node2
RSB1(become master from recovery)
ocfs2_setattr()
ocfs2_inode_lock(NULL->EX)
/* dlm_lock() return the stale lvb without setting DLM_SBF_VALNOTVALID */
ocfs2_meta_lvb_is_trustable() return 1 /* so we don't refresh inode from disk */
ocfs2_truncate_file()
mlog_bug_on_msg(disk isize != i_size_read(inode)) /* crash! */
The fix is quite straightforward. We keep to set DLM_LKF_VALBLK flag
for dlm_lock() if the lock resource type needs LVB and the fsdlm plugin
is uesed.
Link: http://lkml.kernel.org/r/1481275846-6604-1-git-send-email-zren@suse.com Signed-off-by: Eric Ren <zren@suse.com> Reviewed-by: Joseph Qi <jiangqi903@gmail.com> Cc: Mark Fasheh <mfasheh@versity.com> Cc: Joel Becker <jlbec@evilplan.org> Cc: Junxiao Bi <junxiao.bi@oracle.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Michal Hocko [Wed, 11 Jan 2017 00:57:30 +0000 (16:57 -0800)]
bpf: do not use KMALLOC_SHIFT_MAX
Commit 01b3f52157ff ("bpf: fix allocation warnings in bpf maps and
integer overflow") has added checks for the maximum allocateable size.
It (ab)used KMALLOC_SHIFT_MAX for that purpose.
While this is not incorrect it is not very clean because we already have
KMALLOC_MAX_SIZE for this very reason so let's change both checks to use
KMALLOC_MAX_SIZE instead.
The original motivation for using KMALLOC_SHIFT_MAX was to work around
an incorrect KMALLOC_MAX_SIZE which could lead to allocation warnings
but it is no longer needed since "slab: make sure that KMALLOC_MAX_SIZE
will fit into MAX_ORDER".
Link: http://lkml.kernel.org/r/20161220130659.16461-3-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Acked-by: Christoph Lameter <cl@linux.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Andrey Konovalov <andreyknvl@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The issue is caused by a lack of size check for the request size in
ep_write_iter which should be fixed. It, however, points to another
problem, that SLUB defines KMALLOC_MAX_SIZE too large because the its
KMALLOC_SHIFT_MAX is (MAX_ORDER + PAGE_SHIFT) which means that the
resulting page allocator request might be MAX_ORDER which is too large
(see __alloc_pages_slowpath).
The same applies to the SLOB allocator which allows even larger sizes.
Make sure that they are capped properly and never request more than
MAX_ORDER order.
Link: http://lkml.kernel.org/r/20161220130659.16461-2-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Reported-by: Andrey Konovalov <andreyknvl@google.com> Acked-by: Christoph Lameter <cl@linux.com> Cc: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Ross Zwisler [Wed, 11 Jan 2017 00:57:24 +0000 (16:57 -0800)]
dax: wrprotect pmd_t in dax_mapping_entry_mkclean
Currently dax_mapping_entry_mkclean() fails to clean and write protect
the pmd_t of a DAX PMD entry during an *sync operation. This can result
in data loss in the following sequence:
1) mmap write to DAX PMD, dirtying PMD radix tree entry and making the
pmd_t dirty and writeable
2) fsync, flushing out PMD data and cleaning the radix tree entry. We
currently fail to mark the pmd_t as clean and write protected.
3) more mmap writes to the PMD. These don't cause any page faults since
the pmd_t is dirty and writeable. The radix tree entry remains clean.
4) fsync, which fails to flush the dirty PMD data because the radix tree
entry was clean.
5) crash - dirty data that should have been fsync'd as part of 4) could
still have been in the processor cache, and is lost.
Fix this by marking the pmd_t clean and write protected in
dax_mapping_entry_mkclean(), which is called as part of the fsync
operation 2). This will cause the writes in step 3) above to generate
page faults where we'll re-dirty the PMD radix tree entry, resulting in
flushes in the fsync that happens in step 4).
Fixes: 4b4bb46d00b3 ("dax: clear dirty entry tags on cache flush") Link: http://lkml.kernel.org/r/1482272586-21177-3-git-send-email-ross.zwisler@linux.intel.com Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com> Reviewed-by: Jan Kara <jack@suse.cz> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Christoph Hellwig <hch@lst.de> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Jan Kara <jack@suse.cz> Cc: Matthew Wilcox <mawilcox@microsoft.com> Cc: Dave Hansen <dave.hansen@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Ross Zwisler [Wed, 11 Jan 2017 00:57:21 +0000 (16:57 -0800)]
mm: add follow_pte_pmd()
Patch series "Write protect DAX PMDs in *sync path".
Currently dax_mapping_entry_mkclean() fails to clean and write protect
the pmd_t of a DAX PMD entry during an *sync operation. This can result
in data loss, as detailed in patch 2.
This series is based on Dan's "libnvdimm-pending" branch, which is the
current home for Jan's "dax: Page invalidation fixes" series. You can
find a working tree here:
Similar to follow_pte(), follow_pte_pmd() allows either a PTE leaf or a
huge page PMD leaf to be found and returned.
Link: http://lkml.kernel.org/r/1482272586-21177-2-git-send-email-ross.zwisler@linux.intel.com Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com> Suggested-by: Dave Hansen <dave.hansen@intel.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Christoph Hellwig <hch@lst.de> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Jan Kara <jack@suse.cz> Cc: Matthew Wilcox <mawilcox@microsoft.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/thp/pagecache/collapse: free the pte page table on collapse for thp page cache.
With THP page cache, when trying to build a huge page from regular pte
pages, we just clear the pmd entry. We will take another fault and at
that point we will find the huge page in the radix tree, thereby using
the huge page to complete the page fault
The second fault path will allocate the needed pgtable_t page for archs
like ppc64. So no need to deposit the same in collapse path.
Depositing them in the collapse path resulting in a pgtable_t memory
leak also giving errors like
BUG: non-zero nr_ptes on freeing mm: 3
Fixes: 953c66c2b22a ("mm: THP page cache support for ppc64") Link: http://lkml.kernel.org/r/20161212163428.6780-2-aneesh.kumar@linux.vnet.ibm.com Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The crux of the problem is that once we insert a 4k zero page, all
locking from then on is done in terms of that 4k zero page and any
additional threads sleeping on the empty DAX entry will never be woken.
Fix this by waking all sleepers when we replace the DAX radix tree entry
with a 4k zero page. This will allow all sleeping threads to
successfully transition from locking based on the DAX empty entry to
locking on the 4k zero page.
With the test case reported by Xiong this happens very regularly in my
test setup, with some runs resulting in 9+ threads in this deadlocked
state. With this fix I've been able to run that same test dozens of
times in a loop without issue.
Fixes: ac401cc78242 ("dax: New fault locking") Link: http://lkml.kernel.org/r/1483479365-13607-1-git-send-email-ross.zwisler@linux.intel.com Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com> Reported-by: Xiong Zhou <xzhou@redhat.com> Reviewed-by: Jan Kara <jack@suse.cz> Cc: <stable@vger.kernel.org> [4.7+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
I have noticed that two different descriptions for B: entries in
MAINTAINERS were merged: commit 686564434e88 ("MAINTAINERS: Add bug
tracking system location entry type") and 2de2bd95f456 ("MAINTAINERS:
add "B:" for URI where to file bugs").
This patch keeps the description from 2de2bd95f456. There has been a
discussion [1] about whether this more detailed description is useful
and what it exactly implies. I find it more useful and general, and the
author of 686564434e88 agreed in the end that either is fine.
Herbert Xu [Tue, 10 Jan 2017 20:24:15 +0000 (12:24 -0800)]
gro: Disable frag0 optimization on IPv6 ext headers
The GRO fast path caches the frag0 address. This address becomes
invalid if frag0 is modified by pskb_may_pull or its variants.
So whenever that happens we must disable the frag0 optimization.
This is usually done through the combination of gro_header_hard
and gro_header_slow, however, the IPv6 extension header path did
the pulling directly and would continue to use the GRO fast path
incorrectly.
This patch fixes it by disabling the fast path when we enter the
IPv6 extension header path.
Fixes: 78a478d0efd9 ("gro: Inline skb_gro_header and cache frag0 virtual address") Reported-by: Slava Shwartsman <slavash@mellanox.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Herbert Xu [Tue, 10 Jan 2017 20:24:01 +0000 (12:24 -0800)]
gro: Enter slow-path if there is no tailroom
The GRO path has a fast-path where we avoid calling pskb_may_pull
and pskb_expand by directly accessing frag0. However, this should
only be done if we have enough tailroom in the skb as otherwise
we'll have to expand it later anyway.
This patch adds the check by capping frag0_len with the skb tailroom.
Fixes: cb18978cbf45 ("gro: Open-code final pskb_may_pull") Reported-by: Slava Shwartsman <slavash@mellanox.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Martin KaFai Lau [Tue, 10 Jan 2017 17:41:49 +0000 (09:41 -0800)]
mlx4: Return EOPNOTSUPP instead of ENOTSUPP
In commit b45f0674b997 ("mlx4: xdp: Allow raising MTU up to one page minus eth and vlan hdrs"),
it changed EOPNOTSUPP to ENOTSUPP by mistake. This patch fixes it.
Fixes: b45f0674b997 ("mlx4: xdp: Allow raising MTU up to one page minus eth and vlan hdrs") Signed-off-by: Martin KaFai Lau <kafai@fb.com> Acked-by: Saeed Mahameed <saeedm@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Julian Wiedmann [Tue, 10 Jan 2017 16:10:34 +0000 (17:10 +0100)]
net/af_iucv: don't use paged skbs for TX on HiperSockets
With commit e53743994e21
("af_iucv: use paged SKBs for big outbound messages"),
we transmit paged skbs for both of AF_IUCV's transport modes
(IUCV or HiperSockets).
The qeth driver for Layer 3 HiperSockets currently doesn't
support NETIF_F_SG, so these skbs would just be linearized again
by the stack.
Avoid that overhead by using paged skbs only for IUCV transport.
cc stable, since this also circumvents a significant skb leak when
sending large messages (where the skb then needs to be linearized).
Signed-off-by: Julian Wiedmann <jwi@linux.vnet.ibm.com> Signed-off-by: Ursula Braun <ubraun@linux.vnet.ibm.com> Cc: <stable@vger.kernel.org> # v4.8+ Fixes: e53743994e21 ("af_iucv: use paged SKBs for big outbound messages") Signed-off-by: David S. Miller <davem@davemloft.net>
Anna, Suman [Tue, 10 Jan 2017 03:48:56 +0000 (21:48 -0600)]
net: add the AF_QIPCRTR entries to family name tables
Commit bdabad3e363d ("net: Add Qualcomm IPC router") introduced a
new address family. Update the family name tables accordingly so
that the lockdep initialization can use the proper names for this
family.
Cc: Courtney Cavin <courtney.cavin@sonymobile.com> Cc: Bjorn Andersson <bjorn.andersson@linaro.org> Signed-off-by: Suman Anna <s-anna@ti.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Stephen Boyd [Mon, 9 Jan 2017 22:31:58 +0000 (14:31 -0800)]
net: qrtr: Mark 'buf' as little endian
Failure to mark this pointer as __le32 causes checkers like
sparse to complain:
net/qrtr/qrtr.c:274:16: warning: incorrect type in assignment (different base types)
net/qrtr/qrtr.c:274:16: expected unsigned int [unsigned] [usertype] <noident>
net/qrtr/qrtr.c:274:16: got restricted __le32 [usertype] <noident>
net/qrtr/qrtr.c:275:16: warning: incorrect type in assignment (different base types)
net/qrtr/qrtr.c:275:16: expected unsigned int [unsigned] [usertype] <noident>
net/qrtr/qrtr.c:275:16: got restricted __le32 [usertype] <noident>
net/qrtr/qrtr.c:276:16: warning: incorrect type in assignment (different base types)
net/qrtr/qrtr.c:276:16: expected unsigned int [unsigned] [usertype] <noident>
net/qrtr/qrtr.c:276:16: got restricted __le32 [usertype] <noident>
Silence it.
Cc: Bjorn Andersson <bjorn.andersson@linaro.org> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> Acked-by: Bjorn Andersson <bjorn.andersson@linaro.org> Signed-off-by: David S. Miller <davem@davemloft.net>
projects / karo-tx-linux.git / log