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From: "Rafael J. Wysocki" <rjw@sisk.pl>
To: Andrea Righi <righi.andrea@gmail.com>
Subject: Re: [PATCH -mmotm] fbmem: fix fb_info->lock and mm->mmap_sem circular locking dependency
Date: Thu, 5 Feb 2009 02:49:25 +0100
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Cc: Andrew Morton <akpm@linux-foundation.org>,
       Andrey Borzenkov <arvidjaar@mail.ru>,
       Geert Uytterhoeven <geert@linux-m68k.org>,
       "Antonino A. Daplas" <adaplas@gmail.com>,
       linux-fbdev-devel@lists.sourceforge.net,
       linux-pm@lists.linux-foundation.org, linux-kernel@vger.kernel.org,
       Dave Jones <davej@redhat.com>,
       Harvey Harrison <harvey.harrison@gmail.com>,
       Johannes Weiner <hannes@cmpxchg.org>,
       Stefan Richter <stefanr@s5r6.in-berlin.de>
References: <498817E2.3020008@gmail.com> <1233783983-28802-1-git-send-email-righi.andrea@gmail.com> <200902050058.31680.rjw@sisk.pl>
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On Thursday 05 February 2009, Rafael J. Wysocki wrote:
> On Wednesday 04 February 2009, Andrea Righi wrote:
> > Fix this circular locking dependencies in the frame buffer console
> > driver pushing down the mutex fb_info->lock.
> > 
> > Circular locking dependecies occur calling the blocking
> > fb_notifier_call_chain() with fb_info->lock held. Notifier callbacks can
> > try to acquire mm->mmap_sem, while fb_mmap() acquires the locks in the
> > reverse order mm->mmap_sem => fb_info->lock.
> 
> Does this fix a Bugzilla bug?  If so, then which one?

Never mind, found it.

Thanks,
Rafael