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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - glXSwapIntervalMESA crashes when making use of GLX_MESA_multithread_makecurrent"
href="https://bugs.freedesktop.org/show_bug.cgi?id=89562">89562</a>
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<th>Summary</th>
<td>glXSwapIntervalMESA crashes when making use of GLX_MESA_multithread_makecurrent
</td>
</tr>
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<th>Product</th>
<td>Mesa
</td>
</tr>
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<th>Version</th>
<td>git
</td>
</tr>
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<th>Hardware</th>
<td>x86-64 (AMD64)
</td>
</tr>
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<th>OS</th>
<td>Linux (All)
</td>
</tr>
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<th>Status</th>
<td>NEW
</td>
</tr>
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<th>Severity</th>
<td>normal
</td>
</tr>
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<th>Priority</th>
<td>medium
</td>
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<th>Component</th>
<td>GLX
</td>
</tr>
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<th>Assignee</th>
<td>mesa-dev@lists.freedesktop.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>jlegg@feralinteractive.com
</td>
</tr>
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<th>QA Contact</th>
<td>mesa-dev@lists.freedesktop.org
</td>
</tr></table>
<p>
<div>
<pre>Created <span class=""><a href="attachment.cgi?id=114264" name="attach_114264" title="test case">attachment 114264</a> <a href="attachment.cgi?id=114264&action=edit" title="test case">[details]</a></span>
test case
If two threads have the same current glX context, as permitted by
GLX_MESA_multithread_makecurrent, then calling glXSwapIntervalMESA results in
invoking dri2SetSwapInterval with the pdraw argument set to NULL.
dri2SetSwapInterval then dereferences pdraw, causing a segmentation fault. The
attached program reproduces this.
You can also reproduce the same crash by letting a thread exit with a context
bound and then making the context current on another thread and calling
glXSwapIntervalMESA there (this seems a bit dirty, but if there is no
requirement to unbind GL contexts before exiting threads, then this method
doesn't require GLX_MESA_multithread_makecurrent). If you add -DTEST2 to the
compiler flags when compiling the attached file, this crash will be reproduced
instead.
This affects at least Mesa 10.4.3, 10.5, and git master at revision
48b0a3c1c9d829a9b1d401afb2796b35df94a5d7.</pre>
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