From: Dave Jones <davej@redhat.com>
To: Ming Lei <tom.leiming@gmail.com>
Cc: Linux Kernel <linux-kernel@vger.kernel.org>,
Thomas Gleixner <tglx@linutronix.de>
Subject: Re: lockdep trace from posix timers
Date: Thu, 16 Aug 2012 10:03:56 -0400 [thread overview]
Message-ID: <20120816140356.GA1538@redhat.com> (raw)
In-Reply-To: <CACVXFVO-_bP33syDr22TkX2Rsfhb6rNmUNBtsQBnnyqJxdXRyw@mail.gmail.com>
On Thu, Aug 16, 2012 at 08:54:31PM +0800, Ming Lei wrote:
> On Sat, Jul 28, 2012 at 12:20 AM, Dave Jones <davej@redhat.com> wrote:
> > On Tue, Jul 24, 2012 at 04:36:13PM -0400, Dave Jones wrote:
> > > Linus tree as of 5fecc9d8f59e765c2a48379dd7c6f5cf88c7d75a
> > >
> > > Dave
> > >
> > > ======================================================
> > > [ INFO: HARDIRQ-safe -> HARDIRQ-unsafe lock order detected ]
> > > 3.5.0+ #122 Not tainted
> > > ------------------------------------------------------
> > > trinity-child2/5327 [HC0[0]:SC0[0]:HE0:SE1] is trying to acquire:
> > > blocked: (tasklist_lock){.+.+..}, instance: ffffffff81c05098, at: [<ffffffff8109762b>] posix_cpu_timer_del+0x2b/0xe0
> > >
> > > and this task is already holding:
> > > blocked: (&(&new_timer->it_lock)->rlock){-.-...}, instance: ffff880143bce170, at: [<ffffffff81093d49>] __lock_timer+0x89/0x1f0
> > > which would create a new lock dependency:
> > > (&(&new_timer->it_lock)->rlock){-.-...} -> (tasklist_lock){.+.+..}
> > >
> > > but this new dependency connects a HARDIRQ-irq-safe lock:
> > > (&(&new_timer->it_lock)->rlock){-.-...}
> > > ... which became HARDIRQ-irq-safe at:
> >
> > Shall I start bisecting this ? I can trigger it very easily, but if you
> > can give me a set of commits to narrow down, it'll speed up the bisection.
>
> It should a real possible deadlock, could you test the below patch to
> see if it can fix the warning?
I've not managed to hit it in a while. It seems very dependant upon
specific builds for some reason. Very strange.
Dave
next prev parent reply other threads:[~2012-08-16 14:04 UTC|newest]
Thread overview: 54+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-07-24 20:36 lockdep trace from posix timers Dave Jones
2012-07-27 16:20 ` Dave Jones
2012-08-16 12:54 ` Ming Lei
2012-08-16 14:03 ` Dave Jones [this message]
2012-08-16 18:07 ` Peter Zijlstra
2012-08-17 15:14 ` Oleg Nesterov
2012-08-17 15:17 ` Oleg Nesterov
2012-08-17 16:40 ` task_work_add() should not succeed unconditionally (Was: lockdep trace from posix timers) Oleg Nesterov
2012-08-20 7:15 ` lockdep trace from posix timers Peter Zijlstra
2012-08-20 11:44 ` Peter Zijlstra
2012-08-20 11:46 ` Peter Zijlstra
2012-08-20 11:50 ` Peter Zijlstra
2012-08-20 12:19 ` Steven Rostedt
2012-08-20 12:20 ` Peter Zijlstra
2012-08-20 14:59 ` Oleg Nesterov
2012-08-20 15:10 ` Peter Zijlstra
2012-08-20 15:27 ` Peter Zijlstra
2012-08-20 15:32 ` Oleg Nesterov
2012-08-20 15:46 ` Peter Zijlstra
2012-08-20 15:58 ` Oleg Nesterov
2012-08-20 16:03 ` Peter Zijlstra
2012-08-20 15:05 ` Oleg Nesterov
2012-08-20 15:12 ` Peter Zijlstra
2012-08-20 15:41 ` Oleg Nesterov
2012-08-20 15:56 ` Peter Zijlstra
2012-08-20 16:10 ` Oleg Nesterov
2012-08-20 16:19 ` Peter Zijlstra
2012-08-20 16:23 ` Oleg Nesterov
2012-08-21 18:27 ` Oleg Nesterov
2012-08-21 18:34 ` Oleg Nesterov
2012-08-24 18:56 ` Oleg Nesterov
2012-08-26 19:11 ` [PATCH 0/4] (Was: lockdep trace from posix timers) Oleg Nesterov
2012-08-26 19:12 ` [PATCH 1/4] task_work: make task_work_add() lockless Oleg Nesterov
2012-09-14 6:08 ` [tip:core/urgent] task_work: Make " tip-bot for Oleg Nesterov
2012-09-24 19:27 ` [PATCH 1/4] task_work: make " Geert Uytterhoeven
2012-09-24 20:37 ` Oleg Nesterov
2012-08-26 19:12 ` [PATCH 2/4] task_work: task_work_add() should not succeed after exit_task_work() Oleg Nesterov
2012-09-14 6:09 ` [tip:core/urgent] " tip-bot for Oleg Nesterov
2012-08-26 19:12 ` [PATCH 3/4] task_work: revert d35abdb2 "hold task_lock around checks in keyctl" Oleg Nesterov
2012-09-14 6:10 ` [tip:core/urgent] task_work: Revert " hold " tip-bot for Oleg Nesterov
2012-08-26 19:12 ` [PATCH 4/4] task_work: simplify the usage in ptrace_notify() and get_signal_to_deliver() Oleg Nesterov
2012-09-14 6:11 ` [tip:core/urgent] task_work: Simplify " tip-bot for Oleg Nesterov
2012-09-06 18:01 ` [PATCH 0/4] (Was: lockdep trace from posix timers) Oleg Nesterov
2012-09-06 18:35 ` Peter Zijlstra
2012-09-07 13:13 ` Oleg Nesterov
2012-08-28 16:29 ` lockdep trace from posix timers Peter Zijlstra
2012-08-28 17:01 ` Oleg Nesterov
2012-08-28 17:12 ` Oleg Nesterov
2012-08-28 17:28 ` Peter Zijlstra
2012-08-29 15:25 ` Oleg Nesterov
2012-08-20 14:55 ` Oleg Nesterov
2012-08-20 15:43 ` Oleg Nesterov
2012-08-20 15:48 ` Peter Zijlstra
2012-08-20 15:58 ` Oleg Nesterov
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