Re: lockdep trace from kill_fasync (tty) vs account (random)

From: Peter Hurley
Date: Wed Mar 06 2013 - 06:19:48 EST


On Tue, 2013-03-05 at 22:06 -0500, Dave Jones wrote:
> Came home to this on my box that I left fuzz-testing.
>
> [56194.899379] ======================================================
> [56194.899529] [ INFO: possible circular locking dependency detected ]
> [56194.899679] 3.9.0-rc1+ #67 Not tainted
> [56194.899769] -------------------------------------------------------
> [56194.899920] modprobe/14420 is trying to acquire lock:
> [56194.900041] blocked: (&(&new->fa_lock)->rlock){......}, instance: ffff8800c240b4b8, at: [<ffffffff811c31d6>] kill_fasync+0x96/0x2a0
> [56194.900343]
> but task is already holding lock:
> [56194.900478] held: (nonblocking_pool.lock){..-...}, instance: ffffffff81ca99a0, at: [<ffffffff81417909>] account+0x39/0x1c0
> [56194.900765]
> which lock already depends on the new lock.

Hi Dave,

Turns out it's a problem in random.

https://lkml.org/lkml/2013/3/4/295

Regards,
Peter Hurley

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