From: Peter Zijlstra <peterz@infradead.org>
To: Pekka Enberg <penberg@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Sebastian Siewior <sebastian@breakpoint.cc>,
Christoph Lameter <cl@linux-foundation.org>,
Matt Mackall <mpm@selenic.com>,
linux-mm@kvack.org
Subject: Re: possible recursive locking detected cache_alloc_refill() + cache_flusharray()
Date: Wed, 20 Jul 2011 15:30:38 +0200 [thread overview]
Message-ID: <1311168638.5345.80.camel@twins> (raw)
In-Reply-To: <alpine.DEB.2.00.1107201619540.3528@tiger>
On Wed, 2011-07-20 at 16:21 +0300, Pekka Enberg wrote:
> On Sat, 16 Jul 2011, Sebastian Siewior wrote:
> >> just hit the following with full debuging turned on:
> >>
> >> | =============================================
> >> | [ INFO: possible recursive locking detected ]
> >> | 3.0.0-rc7-00088-g1765a36 #64
> >> | ---------------------------------------------
> >> | udevd/1054 is trying to acquire lock:
> >> | (&(&parent->list_lock)->rlock){..-...}, at: [<c00bf640>] cache_alloc_refill+0xac/0x868
> >> |
> >> | but task is already holding lock:
> >> | (&(&parent->list_lock)->rlock){..-...}, at: [<c00be47c>] cache_flusharray+0x58/0x148
> >> |
> >> | other info that might help us debug this:
> >> | Possible unsafe locking scenario:
> >> |
> >> | CPU0
> >> | ----
> >> | lock(&(&parent->list_lock)->rlock);
> >> | lock(&(&parent->list_lock)->rlock);
>
> On Sun, 17 Jul 2011, Thomas Gleixner wrote:
> > Known problem. Pekka is looking into it.
>
> Actually, I kinda was hoping Peter would make it go away. ;-)
>
> Looking at the lockdep report, it's l3->list_lock and I really don't quite
> understand why it started to happen now. There hasn't been any major
> changes in mm/slab.c for a while. Did lockdep become more strict recently?
Not that I know.. :-) I bet -rt just makes it easier to trigger this
weirdness.
Let me try and look at slab.c without my eyes burning out.. I so hate
that code.
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next prev parent reply other threads:[~2011-07-20 13:31 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-07-16 21:18 Sebastian Siewior
2011-07-17 21:34 ` Thomas Gleixner
2011-07-20 13:21 ` Pekka Enberg
2011-07-20 13:30 ` Peter Zijlstra [this message]
2011-07-20 13:52 ` Pekka Enberg
2011-07-20 14:00 ` Christoph Lameter
2011-07-20 15:44 ` Peter Zijlstra
2011-07-21 7:14 ` Sebastian Siewior
2011-07-22 8:17 ` Pekka Enberg
2011-07-22 13:26 ` Peter Zijlstra
2011-07-23 11:22 ` Sebastian Andrzej Siewior
2011-07-28 10:46 ` Pekka Enberg
2011-07-28 10:56 ` Sebastian Andrzej Siewior
2011-07-28 10:56 ` Peter Zijlstra
2011-07-28 10:55 ` Pekka Enberg
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