From: Wang Chen <wangchen@cn.fujitsu.com>
To: Eric Anholt <eric@anholt.net>
Cc: linux-kernel@vger.kernel.org, dri-devel@lists.sourceforge.net
Subject: Re: [PATCH] drm: Fix lock order reversal between mmap_sem and struct_mutex.
Date: Wed, 18 Feb 2009 16:02:20 +0800 [thread overview]
Message-ID: <499BC08C.5000603@cn.fujitsu.com> (raw)
In-Reply-To: <1234918786-854-1-git-send-email-eric@anholt.net>
Eric Anholt said the following on 2009-2-18 8:59:
> The basic problem was
> mmap_sem (do_mmap()) -> struct_mutex (drm_gem_mmap(), i915_gem_fault())
> struct_mutex (i915_gem_execbuffer()) -> mmap_sem (copy_from/to_user())
>
> We have plenty of places where we want to hold device state the same
> (struct_mutex) while we move a non-trivial amount of data
> (copy_from/to_user()), such as i915_gem_pwrite(). Solve this by moving the
> easy things that needed struct_mutex with mmap_sem held to using a lock to
> cover just those data structures (offset hash and offset manager), and do
> trylock and reschedule in fault.
>
Eric, I tested the patch.
But following bug still doesn't disappear.
http://bugzilla.kernel.org/show_bug.cgi?id=12419
next prev parent reply other threads:[~2009-02-18 8:02 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-02-18 0:59 [PATCH] drm: Fix lock order reversal between mmap_sem and struct_mutex Eric Anholt
2009-02-18 8:02 ` Wang Chen [this message]
2009-02-18 16:38 ` [PATCH] drm: Take mmap_sem up front to avoid lock order violations krh
2009-02-19 9:19 ` Peter Zijlstra
2009-02-19 10:33 ` Peter Zijlstra
2009-02-19 14:49 ` Kristian Høgsberg
2009-02-19 15:17 ` Nick Piggin
2009-02-19 15:21 ` Kristian Høgsberg
2009-02-19 12:57 ` Nick Piggin
2009-02-21 2:33 ` Eric Anholt
2009-02-18 15:08 ` [PATCH] drm: Fix lock order reversal between mmap_sem and struct_mutex Peter Zijlstra
2009-02-19 21:02 ` Thomas Hellstrom
2009-02-19 22:26 ` Peter Zijlstra
2009-02-20 2:04 ` Eric Anholt
2009-02-20 7:36 ` Peter Zijlstra
2009-02-25 8:15 ` Eric Anholt
2009-02-25 8:54 ` Thomas Hellström
2009-02-25 9:07 ` Peter Zijlstra
2009-02-20 8:31 ` Thomas Hellstrom
2009-02-20 8:47 ` Peter Zijlstra
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