Messages in this thread Patch in this message | | | Date | Fri, 14 Apr 2017 02:30:28 -0700 | From | tip-bot for Thomas Gleixner <> | Subject | [tip:locking/core] futex: Avoid freeing an active timer |
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Commit-ID: 97181f9bd57405b879403763284537e27d46963d Gitweb: http://git.kernel.org/tip/97181f9bd57405b879403763284537e27d46963d Author: Thomas Gleixner <tglx@linutronix.de> AuthorDate: Mon, 10 Apr 2017 18:03:36 +0200 Committer: Ingo Molnar <mingo@kernel.org> CommitDate: Fri, 14 Apr 2017 10:29:53 +0200
futex: Avoid freeing an active timer
Alexander reported a hrtimer debug_object splat:
ODEBUG: free active (active state 0) object type: hrtimer hint: hrtimer_wakeup (kernel/time/hrtimer.c:1423)
debug_object_free (lib/debugobjects.c:603) destroy_hrtimer_on_stack (kernel/time/hrtimer.c:427) futex_lock_pi (kernel/futex.c:2740) do_futex (kernel/futex.c:3399) SyS_futex (kernel/futex.c:3447 kernel/futex.c:3415) do_syscall_64 (arch/x86/entry/common.c:284) entry_SYSCALL64_slow_path (arch/x86/entry/entry_64.S:249)
Which was caused by commit:
cfafcd117da0 ("futex: Rework futex_lock_pi() to use rt_mutex_*_proxy_lock()")
... losing the hrtimer_cancel() in the shuffle. Where previously the hrtimer_cancel() was done by rt_mutex_slowlock() we now need to do it manually.
Reported-by: Alexander Levin <alexander.levin@verizon.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Fixes: cfafcd117da0 ("futex: Rework futex_lock_pi() to use rt_mutex_*_proxy_lock()") Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1704101802370.2906@nanos Signed-off-by: Ingo Molnar <mingo@kernel.org> --- kernel/futex.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/kernel/futex.c b/kernel/futex.c index c3eebcd..7ac1676 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -2736,8 +2736,10 @@ out_unlock_put_key: out_put_key: put_futex_key(&q.key); out: - if (to) + if (to) { + hrtimer_cancel(&to->timer); destroy_hrtimer_on_stack(&to->timer); + } return ret != -EINTR ? ret : -ERESTARTNOINTR; uaddr_faulted:
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