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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - [PATCH] Sigsegv in i965 driver (get_stencil_miptree), plasma crashes after login"
href="https://bugs.freedesktop.org/show_bug.cgi?id=92103">92103</a>
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<th>Summary</th>
<td>[PATCH] Sigsegv in i965 driver (get_stencil_miptree), plasma crashes after login
</td>
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<th>Product</th>
<td>Mesa
</td>
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<th>Version</th>
<td>10.6
</td>
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<th>Hardware</th>
<td>x86-64 (AMD64)
</td>
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<th>OS</th>
<td>Linux (All)
</td>
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<th>Status</th>
<td>NEW
</td>
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<th>Severity</th>
<td>normal
</td>
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<th>Priority</th>
<td>medium
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<th>Component</th>
<td>Drivers/DRI/i965
</td>
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<th>Assignee</th>
<td>idr@freedesktop.org
</td>
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<th>Reporter</th>
<td>ugilio@gmail.com
</td>
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<th>QA Contact</th>
<td>intel-3d-bugs@lists.freedesktop.org
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<pre>Created <span class=""><a href="attachment.cgi?id=118428" name="attach_118428" title="Stack trace">attachment 118428</a> <a href="attachment.cgi?id=118428&action=edit" title="Stack trace">[details]</a></span>
Stack trace
This bug was originally reported on RedHat's bugzilla for Fedora 22:
<a href="https://bugzilla.redhat.com/show_bug.cgi?id=1266025">https://bugzilla.redhat.com/show_bug.cgi?id=1266025</a>
Description of problem:
On the machine I use at work sometimes plasma crashes after the login, before
showing the KDE desktop. Investigation with gdb might have shown the cause of
the problem.
Version-Release number of selected component (if applicable):
mesa-dri-drivers-10.6.3-3.20150729.fc22.x86_64
How reproducible:
Sometimes
Steps to Reproduce:
1. In KDM, perform the login
Actual results:
Sometimes plasma crashes before showing the desktop
Expected results:
Plasma should start and show the desktop
Additional info:
I Launched gdb from the KDE crash handler (drkonqi?), see attached stack trace.
The crash happened at brw_misc_state.c:215, that is:
(gdb) list
210 static struct intel_mipmap_tree *
211 get_stencil_miptree(struct intel_renderbuffer *irb)
212 {
213 if (!irb)
214 return NULL;
215 if (irb->mt->stencil_mt)
216 return irb->mt->stencil_mt;
217 return irb->mt;
218 }
219
It turns out that irb->mt was null:
(gdb) print irb->mt
$3 = (struct intel_mipmap_tree *) 0x0
I modified the line to read
if (irb->mt && irb->mt->stencil_mt)
(see the attached patch) and so far (a couple of restarts, a shutdown, and a
tenth of logouts/logins) no crash happened.
However, since the crash is not always reproducible, I cannot be 100% sure.
The video card is
00:02.0 VGA compatible controller: Intel Corporation 4 Series Chipset
Integrated Graphics Controller (rev 03)
I am using the intel driver with UXA acceleration method (not SNA).
Glxinfo says:
server glx vendor string: SGI
server glx version string: 1.4
client glx vendor string: Mesa Project and SGI
client glx version string: 1.4
OpenGL vendor string: Intel Open Source Technology Center
OpenGL renderer string: Mesa DRI Intel(R) G45/G43
OpenGL version string: 2.1 Mesa 10.6.3 (git-ccef890)
OpenGL shading language version string: 1.20
OpenGL ES profile version string: OpenGL ES 2.0 Mesa 10.6.3 (git-ccef890)
OpenGL ES profile shading language version string: OpenGL ES GLSL ES 1.0.16
I think this is not a duplicate of bugs like this:
<a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED FIXED - KWin crash in brw_workaround_depthstencil_alignment on Haswell"
href="show_bug.cgi?id=77402">https://bugs.freedesktop.org/show_bug.cgi?id=77402</a>
because it was fixed long ago.</pre>
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