From: Peter Zijlstra <peterz@infradead.org>
To: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Tejun Heo <tj@kernel.org>,
"linux-kernel@vger.kernel.org >> Linux Kernel Mailing List"
<linux-kernel@vger.kernel.org>,
linux-s390 <linux-s390@vger.kernel.org>,
KVM list <kvm@vger.kernel.org>, Oleg Nesterov <oleg@redhat.com>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Subject: Re: regression 4.4: deadlock in with cgroup percpu_rwsem
Date: Mon, 18 Jan 2016 19:32:05 +0100 [thread overview]
Message-ID: <20160118183205.GW6357@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <56990C9E.7020801@de.ibm.com>
On Fri, Jan 15, 2016 at 04:13:34PM +0100, Christian Borntraeger wrote:
> > Yes, the deadlock is gone and the system is still running.
> > After some time I had the following WARN in the logs, though.
> > Not sure yet if that is related.
> >
> > [25331.763607] DEBUG_LOCKS_WARN_ON(lock->owner != current)
> > [25331.763630] ------------[ cut here ]------------
> > [25331.763634] WARNING: at kernel/locking/mutex-debug.c:80
> I restarted the test with panic_on_warn. Hopefully I can get a dump to check
> which mutex this was.
Hard to reproduce warnings like this tend to point towards memory
corruption. Someone stepped on the mutex value and tickles the sanity
check.
With lockdep and debugging enabled the mutex gets quite a bit bigger, so
it gets more likely to be hit by 'random' corruption.
The locking in seq_read() seems rather straight forward.
next prev parent reply other threads:[~2016-01-18 18:32 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-14 11:19 regression 4.4: deadlock in with cgroup percpu_rwsem Christian Borntraeger
2016-01-14 13:38 ` Christian Borntraeger
2016-01-14 14:04 ` Nikolay Borisov
2016-01-14 14:08 ` Christian Borntraeger
2016-01-14 14:27 ` Nikolay Borisov
2016-01-14 17:15 ` Christian Borntraeger
2016-01-14 19:56 ` Tejun Heo
2016-01-15 7:30 ` Christian Borntraeger
2016-01-15 15:13 ` Christian Borntraeger
2016-01-18 18:32 ` Peter Zijlstra [this message]
2016-01-18 18:48 ` Christian Borntraeger
2016-01-19 9:55 ` Heiko Carstens
2016-01-19 19:36 ` Christian Borntraeger
2016-01-19 19:38 ` Tejun Heo
2016-01-20 7:07 ` Heiko Carstens
2016-01-20 10:15 ` Christian Borntraeger
2016-01-20 10:30 ` Peter Zijlstra
2016-01-20 10:47 ` Peter Zijlstra
2016-01-20 15:30 ` Tejun Heo
2016-01-20 16:04 ` Tejun Heo
2016-01-20 16:49 ` Peter Zijlstra
2016-01-20 16:56 ` Tejun Heo
2016-01-23 2:03 ` Paul E. McKenney
2016-01-25 8:49 ` Christoph Hellwig
2016-01-25 19:38 ` Tejun Heo
2016-01-26 14:51 ` Christoph Hellwig
2016-01-26 15:28 ` Tejun Heo
2016-01-26 16:41 ` Christoph Hellwig
2016-01-20 10:53 ` Peter Zijlstra
2016-01-21 8:23 ` Christian Borntraeger
2016-01-21 9:27 ` Peter Zijlstra
2016-01-15 16:40 ` Tejun Heo
2016-01-19 17:18 ` [PATCH cgroup/for-4.5-fixes] cpuset: make mm migration asynchronous Tejun Heo
2016-01-22 14:24 ` Christian Borntraeger
2016-01-22 15:22 ` Tejun Heo
2016-01-22 15:45 ` Christian Borntraeger
2016-01-22 15:47 ` Tejun Heo
2016-01-22 15:23 ` Tejun Heo
2016-01-21 20:31 ` [PATCH 1/2] cgroup: make sure a parent css isn't offlined before its children Tejun Heo
2016-01-21 20:32 ` [PATCH 2/2] cgroup: make sure a parent css isn't freed " Tejun Heo
2016-01-22 15:45 ` [PATCH v2 " Tejun Heo
2016-01-21 21:24 ` [PATCH 1/2] cgroup: make sure a parent css isn't offlined " Peter Zijlstra
2016-01-21 21:28 ` Tejun Heo
2016-01-22 8:18 ` Christian Borntraeger
2016-02-29 11:13 ` [tip:sched/core] sched/cgroup: Fix cgroup entity load tracking tear-down tip-bot for Peter Zijlstra
2016-01-22 15:45 ` [PATCH v2 1/2] cgroup: make sure a parent css isn't offlined before its children Tejun Heo
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