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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - No backtrace on Linux for crashes due to stack overflow"
href="https://bugs.llvm.org/show_bug.cgi?id=47899">47899</a>
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</tr>
<tr>
<th>Summary</th>
<td>No backtrace on Linux for crashes due to stack overflow
</td>
</tr>
<tr>
<th>Product</th>
<td>libraries
</td>
</tr>
<tr>
<th>Version</th>
<td>trunk
</td>
</tr>
<tr>
<th>Hardware</th>
<td>PC
</td>
</tr>
<tr>
<th>OS</th>
<td>Linux
</td>
</tr>
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<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>enhancement
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
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<th>Component</th>
<td>Support Libraries
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>jannh@google.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr></table>
<p>
<div>
<pre>The signal handlers LLVM installs in RegisterHandlers() (used for things
like printing a stack trace) use SA_ONSTACK so that on stack overflow,
the signal handler still has a stack from which it can run.
However, CrashRecoveryContext overwrites those signal handlers with ones
without SA_ONSTACK. Therefore, if the stack overflows while a
CrashRecoveryContext is active, the kernel fails to write a signal frame
and terminates the process, which means that LLVM won't print a
backtrace.
You can e.g. test this by calling an endlessly recursing function
directly below the call to llvm::CrashRecoveryContext::Enable() in
clang/tools/driver/driver.cpp.
I have sent a patch for this for review: <a href="https://reviews.llvm.org/D89442">https://reviews.llvm.org/D89442</a></pre>
</div>
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