Re: [PATCH 6/6] drm/i915: Fix lock order reversal in GEMrelocation entry copying. -- makes X hang

[Eric Anholt]

On Mon, 2009-03-30 at 12:00 +0200, Florian Mickler wrote:
> Hi!
> 
> On Wed, 25 Mar 2009 14:45:10 -0700
> Eric Anholt <eric@xxxxxxxxxx> wrote:
> 
> > Signed-off-by: Eric Anholt <eric@xxxxxxxxxx>
> > Reviewed-by: Keith Packard <keithp@xxxxxxxxxx>
> > ---
> >  drivers/gpu/drm/i915/i915_gem.c |  187
> > +++++++++++++++++++++++++++----------- 1 files changed, 133
> > insertions(+), 54 deletions(-)
> > 
> 
> I testet Linus' Git tree @ 5d80f8e5a (merge
> net-2.6) and discovered that X hung after starting up gdm.
> 
> When i start gdm the screen is frozen and X hangs. 
> I was able to bisect it down to 
> 
> 40a5f0decdf050785ebd62b36ad48c869ee4b384 drm/i915: Fix lock order
> reversal in GEM relocation entry copying.
> 
> 
> when hung /proc/[xpid]/stack did contain:
> 
> [<ffffffff8024c13e>] msleep_interruptible+0x2e/0x40
> [<ffffffff80557fdd>] i915_wait_ring+0x17d/0x1d0
> [<ffffffff8056280d>] i915_gem_execbuffer+0xd2d/0xf70
> [<ffffffff80546555>] drm_ioctl+0x1f5/0x320
> [<ffffffff802d8ce5>] vfs_ioctl+0x85/0xa0
> [<ffffffff802d8f0b>] do_vfs_ioctl+0x20b/0x510
> [<ffffffff802d9297>] sys_ioctl+0x87/0xa0
> [<ffffffff8020ba8b>] system_call_fastpath+0x16/0x1b
> [<ffffffffffffffff>] 0xffffffffffffffff
> 
> 
> I reverted that commit now on top of 5d80f8e5a and all 's well .
> 
> 
> My X-Stack is from Git at around 20th march. I will update that now,
> but as it hangs in a kernel syscall, it shouldn't matter?
> 
> Sincerely,
> 
> Florian
> 
> p.s. no kms 

Ouch.  Could you file a bug report using:

http://intellinuxgraphics.org/how_to_report_bug.html

so I've got the information I need to try to reproduce this?

-- 
Eric Anholt
eric@xxxxxxxxxx                         eric.anholt@xxxxxxxxx

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