Bug 91074 - [SKL] starting xterm crashes the xserver with some kernels
Summary: [SKL] starting xterm crashes the xserver with some kernels
Status: RESOLVED NOTOURBUG
Alias: None
Product: xorg
Classification: Unclassified
Component: Driver/intel (show other bugs)
Version: unspecified
Hardware: Other All
: medium normal
Assignee: Chris Wilson
QA Contact: Intel GFX Bugs mailing list
URL:
Whiteboard:
Keywords:
Depends on:
Blocks:
 
Reported: 2015-06-23 15:03 UTC by Timo Aaltonen
Modified: 2015-06-25 14:11 UTC (History)
0 users

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Attachments

Description Timo Aaltonen 2015-06-23 15:03:47 UTC
dumping this here so it's not lost

Starting xterm (and amdcccle too, apparently) crashes X with some kernel versions. Rough bisect shows that v4.1-rc5 is bad and rc6 and up is good.
Comment 1 Chris Wilson 2015-06-24 10:37:11 UTC
I'm hopeful that Timo can do the kernel bisect to find the patch that fixed the crash (so that we have some idea where to look for the underlying bug and decide whether or not it was just a side-effect of the bug the patch fixed), also having an Xorg.0.log from a debug=full run leading up to the crash may shed light onto the trigger in the meantime (though I'm doubtful since the crash looks like generic memory corruption - userptr?).
Comment 2 Timo Aaltonen 2015-06-25 13:26:51 UTC
bisection shows it got fixed by:

commit e88221c50cadade0eb4f7f149f4967d760212695
Author: Ingo Molnar <mingo@kernel.org>
Date:   Wed May 20 11:45:30 2015 +0200

    x86/fpu: Disable XSAVES* support for now


I need to try backporting that commit to the distro kernel to see if it's true..
Comment 3 Timo Aaltonen 2015-06-25 14:07:24 UTC
verified that this commit fixed the crash, phew
Comment 4 Chris Wilson 2015-06-25 14:11:37 UTC
And the patch is cc'ed stable@vger.kernel.org so it means just extra work for poor Timo!

Thanks for the bug report and finding the guilty party. I was worried there for a while.


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