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Message-ID: <1362568771.18799.167.camel@thor.lan>
Subject: Re: lockdep trace from kill_fasync (tty) vs account (random)
From: Peter Hurley <peter@hurleysoftware.com>
To: Dave Jones <davej@redhat.com>
Cc: Linux Kernel <linux-kernel@vger.kernel.org>, Jiri Slaby <jslaby@suse.cz>
Date: Wed, 06 Mar 2013 06:19:31 -0500
In-Reply-To: <20130306030633.GA6567@redhat.com>
References: <20130306030633.GA6567@redhat.com>
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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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