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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Caller Frame Information in x86_64 XRay trampolines is invalid"
href="https://bugs.llvm.org/show_bug.cgi?id=49060">49060</a>
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<th>Summary</th>
<td>Caller Frame Information in x86_64 XRay trampolines is invalid
</td>
</tr>
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<th>Product</th>
<td>XRay
</td>
</tr>
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<th>Version</th>
<td>unspecified
</td>
</tr>
<tr>
<th>Hardware</th>
<td>PC
</td>
</tr>
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<th>OS</th>
<td>Linux
</td>
</tr>
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<th>Status</th>
<td>NEW
</td>
</tr>
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<th>Severity</th>
<td>enhancement
</td>
</tr>
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<th>Priority</th>
<td>P
</td>
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<th>Component</th>
<td>Runtime
</td>
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<th>Assignee</th>
<td>dberris@google.com
</td>
</tr>
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<th>Reporter</th>
<td>elia.f.geretto@gmail.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr></table>
<p>
<div>
<pre>When attempting to unwind the stack from inside an XRay handler, both using
`libunwind` and `gdb`, the stack trace is corrupted.
As an example, this happens when using `backtrace` in GDB:
#0 xray_handler (function_id=<optimized out>, entry_type=ENTRY) at main.c:140
#1 0x000000000041ad5d in __xray_FunctionEntry ()
#2 0x000000000041d250 in .annobin__ZN6__xray18fdrLoggingFinalizeEv.end ()
#3 0x000000000041d1b0 in
.annobin__ZZN6__xrayL19fdrCommonHeaderInfoEvENUlvE_4_FUNEv.end ()
#4 0x000000000041ff60 in ?? ()
#5 0x0000000000000246 in ?? ()
#6 0x000000000041ff2b in print_message () at main.c:159
#7 0x000000000041ff51 in main (argc=0x1, argv=0x0) at main.c:162
The stack trace is correct up to frame 1, but then it gets corrupted. I
verified that this is due to the following ASM macro in which `rsp` is
manipulated without adding the appropriate CFI directives:
<a href="https://github.com/llvm/llvm-project/blob/af48d2bfc23fd188e5ae162b9f5b27de306ab38f/compiler-rt/lib/xray/xray_trampoline_x86_64.S#L83-L87">https://github.com/llvm/llvm-project/blob/af48d2bfc23fd188e5ae162b9f5b27de306ab38f/compiler-rt/lib/xray/xray_trampoline_x86_64.S#L83-L87</a></pre>
</div>
</p>
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