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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org> To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>, stable@vger.kernel.org, Alexander Levin <alexander.levin@verizon.com>, Thomas Gleixner <tglx@linutronix.de>, "Peter Zijlstra (Intel)" <peterz@infradead.org>, Linus Torvalds <torvalds@linux-foundation.org>, Ingo Molnar <mingo@kernel.org>, Zhen Lei <thunder.leizhen@huawei.com>, Joe Korty <joe.korty@concurrent-rt.com> Subject: [PATCH 4.4 09/11] futex: Avoid freeing an active timer Date: Sun, 8 Aug 2021 09:22:44 +0200 [thread overview] Message-ID: <20210808072217.637655944@linuxfoundation.org> (raw) In-Reply-To: <20210808072217.322468704@linuxfoundation.org> From: Thomas Gleixner <tglx@linutronix.de> [ Upstream commit 97181f9bd57405b879403763284537e27d46963d ] 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> Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com> Acked-by: Joe Korty <joe.korty@concurrent-rt.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- kernel/futex.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/kernel/futex.c +++ b/kernel/futex.c @@ -2960,8 +2960,10 @@ 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:
next prev parent reply other threads:[~2021-08-08 7:24 UTC|newest] Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-08-08 7:22 [PATCH 4.4 00/11] 4.4.280-rc1 review Greg Kroah-Hartman 2021-08-08 7:22 ` [PATCH 4.4 01/11] futex: Rename free_pi_state() to put_pi_state() Greg Kroah-Hartman 2021-08-08 7:22 ` [PATCH 4.4 02/11] futex: Cleanup refcounting Greg Kroah-Hartman 2021-08-08 7:22 ` [PATCH 4.4 03/11] futex,rt_mutex: Introduce rt_mutex_init_waiter() Greg Kroah-Hartman 2021-08-08 7:22 ` [PATCH 4.4 04/11] futex: Pull rt_mutex_futex_unlock() out from under hb->lock Greg Kroah-Hartman 2021-08-08 7:22 ` [PATCH 4.4 05/11] futex: Rework futex_lock_pi() to use rt_mutex_*_proxy_lock() Greg Kroah-Hartman 2021-08-08 7:22 ` [PATCH 4.4 06/11] futex: Futex_unlock_pi() determinism Greg Kroah-Hartman 2021-08-08 7:22 ` [PATCH 4.4 07/11] rtmutex: Make wait_lock irq safe Greg Kroah-Hartman 2021-08-08 7:22 ` [PATCH 4.4 08/11] futex: Handle transient "ownerless" rtmutex state correctly Greg Kroah-Hartman 2021-08-08 7:22 ` Greg Kroah-Hartman [this message] 2021-08-08 7:22 ` [PATCH 4.4 10/11] futex,rt_mutex: Fix rt_mutex_cleanup_proxy_lock() Greg Kroah-Hartman 2021-08-08 7:22 ` [PATCH 4.4 11/11] rcu: Update documentation of rcu_read_unlock() Greg Kroah-Hartman 2021-08-08 16:00 ` [PATCH 4.4 00/11] 4.4.280-rc1 review Guenter Roeck 2021-08-10 15:44 ` Greg Kroah-Hartman 2021-08-09 14:14 ` Naresh Kamboju -- strict thread matches above, loose matches on Subject: below -- 2021-08-02 13:46 [PATCH 4.4 00/11] Fix a potential infinite loop in RT futex-pi scenarios Zhen Lei 2021-08-02 13:46 ` [PATCH 4.4 09/11] futex: Avoid freeing an active timer Zhen Lei
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