Bug 92447

Summary: kgem_bo_pair_undo:2847 assertion 'b->exec == &kgem->exec[0] || b->exec == &kgem->exec[1]' failed
Product: xorg Reporter: Laszlo Valko <valko>
Component: Driver/intelAssignee: Chris Wilson <chris>
Status: RESOLVED FIXED QA Contact: Intel GFX Bugs mailing list <intel-gfx-bugs>
Severity: normal    
Priority: medium    
Version: git   
Hardware: x86 (IA32)   
OS: Linux (All)   
Whiteboard:
i915 platform: i915 features:
Attachments:
Description Flags
Xorg.0.log
none
Crash log none

Description Laszlo Valko 2015-10-13 10:08:20 UTC 
Created attachment 118851 [details]
Xorg.0.log

After about 10-15 minutes of uptime, the latest Intel driver crashes with assertion failure message:
kgem_bo_pair_undo:2847 assertion 'b->exec == &kgem->exec[0] || b->exec == &kgem->exec[1]' failed

System: Gentoo
Components used:
- xf86-video-intel 2.99.917 (latest from git 2015-10-09 df72bc57610bb2f58eec9801820ea11628b244eb)
- xorg-server 1.16.4 (with patch https://bugs.freedesktop.org/attachment.cgi?id=94929)

Running applications:
Firefox 38.3.0, Opera 12.16, xterms
Comment 1 Laszlo Valko 2015-10-13 10:13:13 UTC 
The affected symbols from nm for the stack trace:
0002b6e0 t kgem_bo_pair_undo
0000bd7b t sna_poly_fill_rect_tiled_8x8_blt
0000d501 t sna_poly_fill_rect_tiled_nxm_blt
000595a0 t sna_poly_fill_rect_tiled_blt
00060ed0 t sna_fill_spans__gpu
0006bfc0 t sna_poly_fill_polygon
Comment 2 Chris Wilson 2015-10-13 10:31:04 UTC 
Assertion looks valid, and "cannot possibly happen there". If you compiled with --enable-debug=full does the bug still manifest? Could you send me the verbose debug log in that case?
Comment 3 Laszlo Valko 2015-10-13 11:05:48 UTC 
Created attachment 118852 [details]
Crash log

Here's the last 250k lines from the log.
Comment 4 Chris Wilson 2015-10-13 11:24:37 UTC 
Ok, looks like a bogus assertion. Thanks.

commit 6224814b85e8aed75854192ec27aa06163e76d94
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Tue Oct 13 12:20:33 2015 +0100

    sna: Handle proxy objects in undo assertions
    
    Note that we may try to clear a batch containing a proxy object, in
    which case the proxy has a dummy exec entry - so we need to be careful
    in making our assertions.
    
    Reported-by: Laszlo Valko <valko@linux.karinthy.hu>
    Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=92447
    Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Comment 5 Chris Wilson 2015-10-15 13:12:16 UTC 
The assertion should be fixed now.

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