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Message-ID: <20101109092920.GA1542@arch.trippelsdorf.de>
Date: Tue, 9 Nov 2010 10:29:20 +0100
From: Markus Trippelsdorf <markus@...ppelsdorf.de>
To: Thomas Hellstrom <thellstrom@...are.com>
Cc: Jerome Glisse <j.glisse@...il.com>,
"dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"airlied@...ux.ie" <airlied@...ux.ie>,
Michel Dänzer <daenzer@...are.com>
Subject: Re: Radeon RS780 - BUG: unable to handle kernel NULL pointer
dereference
On Mon, Nov 08, 2010 at 11:29:16PM +0100, Thomas Hellstrom wrote:
> On 11/08/2010 09:53 PM, Jerome Glisse wrote:
> >On Mon, Nov 8, 2010 at 2:02 PM, Markus Trippelsdorf
> ><markus@...ppelsdorf.de> wrote:
> >>On Mon, Nov 08, 2010 at 07:43:02PM +0100, Markus Trippelsdorf wrote:
> >>>On Mon, Nov 08, 2010 at 06:07:37PM +0100, Markus Trippelsdorf wrote:
> >>>>On Mon, Nov 08, 2010 at 06:02:21PM +0100, Markus Trippelsdorf wrote:
> >>>>>I can trigger a kernel crash on my system by simply loading this png
> >>>>>image with firefox:
> >>>>>http://mediaarchive.cern.ch/MediaArchive/Photo/Public/2010/1011251/1011251_01/1011251_01-A4-at-144-dpi.jpg
> >>>>Sorry the above link is wrong, this is the right one (that triggers the
> >>>>crash):
> >>>>http://cdsweb.cern.ch/record/1305179/files/HI-150431-630470-huge.png
> >>>I triggered it a few more times and took the attached picture.
> >>>It points to the BUG() call at drivers/gpu/drm/ttm/ttm_bo.c:1628 .
> >>>(Sorry for the bad picture quality)
> >>And here the same BUG in plaintext (should be a bit easier to read):
> >>
> >>Nov 8 19:28:23 arch kernel: ------------[ cut here ]------------
> >>Nov 8 19:28:23 arch kernel: kernel BUG at drivers/gpu/drm/ttm/ttm_bo.c:1628!
> >>
> >Thomas this bug seems to point to a case where we endup trying adding
> >an entry to
> >same offset in the rb tree for addr_space_mm. After reviewing
> >carefully the locking
> >around the rb tree modification& addr_space_mm i am fairly confident
> >that no race can
> >occur. Would you have any idea on what might go wrong here ? I guess i would
> >ultimately need to dump mm& rb tree state when BUG get trigger to try
> >to understand
> >states of things.
>
> I agree there shouldn't be a race in this case.
> The locking around these operations is simple and straightforward.
>
> So this IMHO should either be a memory corruption or a bug in the
> range manager. I've never seen this BUG trigger before. Dumping mm /
> rb tree contents or bisecting should probably find the culprit.
OK I've found the buggy commit by bisection:
e376573f7267390f4e1bdc552564b6fb913bce76 is the first bad commit
commit e376573f7267390f4e1bdc552564b6fb913bce76
Author: Michel Dänzer <daenzer@...are.com>
Date: Thu Jul 8 12:43:28 2010 +1000
drm/radeon: fall back to GTT if bo creation/validation in VRAM fails.
This fixes a problem where on low VRAM cards we'd run out of space for validation.
[airlied: Tested on my M7, Thinkpad T42, compiz works with no problems.]
Signed-off-by: Michel Dänzer <daenzer@...are.com>
Cc: stable@...nel.org
Signed-off-by: Dave Airlie <airlied@...hat.com>
Please note that this is an old commit from 2.6.36-rc. When I revert it the
kernel no longer crashes. Instead I see the following in my dmesg:
[TTM] Failed to find memory space for buffer 0xffff880113e10e48 eviction.
[TTM] No space for ffff880113e10e48 (25650 pages, 102600K, 100M)
[TTM] placement[0]=0x00070002 (1)
[TTM] has_type: 1
[TTM] use_type: 1
[TTM] flags: 0x0000000A
[TTM] gpu_offset: 0xA0000000
[TTM] size: 131072
[TTM] available_caching: 0x00070000
[TTM] default_caching: 0x00010000
[TTM] 0x00000000-0x00000001: 1: used
[TTM] 0x00000001-0x00000011: 16: used
[TTM] 0x00000011-0x00000111: 256: used
[TTM] 0x00000111-0x00000211: 256: used
[TTM] 0x00000211-0x00000248: 55: free
[TTM] 0x00000248-0x0000024c: 4: used
[TTM] 0x0000024c-0x00001976: 5930: free
[TTM] 0x00001976-0x000021aa: 2100: used
[TTM] 0x000021aa-0x0000285f: 1717: free
[TTM] 0x0000285f-0x00002860: 1: used
[TTM] 0x00002860-0x00002873: 19: free
[TTM] 0x00002873-0x000029b3: 320: used
[TTM] 0x000029b3-0x00020000: 120397: free
[TTM] total: 131072, used 2954 free 128118
[drm:radeon_cs_ioctl] *ERROR* Failed to parse relocation -12!
radeon 0000:01:05.0: object_init failed for (117555200, 0x00000004)
[drm:radeon_gem_object_create] *ERROR* Failed to allocate GEM object (117555200, 4, 4096, -12)
radeon 0000:01:05.0: object_init failed for (117555200, 0x00000004)
[drm:radeon_gem_object_create] *ERROR* Failed to allocate GEM object (117555200, 4, 4096, -12)
radeon 0000:01:05.0: object_init failed for (117555200, 0x00000004)
[drm:radeon_gem_object_create] *ERROR* Failed to allocate GEM object (117555200, 4, 4096, -12)
radeon 0000:01:05.0: object_init failed for (117555200, 0x00000004)
[drm:radeon_gem_object_create] *ERROR* Failed to allocate GEM object (117555200, 4, 4096, -12)
radeon 0000:01:05.0: object_init failed for (117555200, 0x00000004)
...
And the following in the xorg log buffer:
Failed to alloc memory
Failed to allocat:
size: : 117555200 bytes
alignment : 0 bytes
domains : 4
...
--
Markus
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