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<base href="https://bugs.llvm.org/">
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - OpenMP profiling via ITT API is broken on Clang 11.x and 12.x (OpenMP runtime crashes)"
href="https://bugs.llvm.org/show_bug.cgi?id=48644">48644</a>
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<th>Summary</th>
<td>OpenMP profiling via ITT API is broken on Clang 11.x and 12.x (OpenMP runtime crashes)
</td>
</tr>
<tr>
<th>Product</th>
<td>OpenMP
</td>
</tr>
<tr>
<th>Version</th>
<td>unspecified
</td>
</tr>
<tr>
<th>Hardware</th>
<td>PC
</td>
</tr>
<tr>
<th>OS</th>
<td>Linux
</td>
</tr>
<tr>
<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>normal
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
<tr>
<th>Component</th>
<td>Runtime Library
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>vitaly.slobodskoy@huawei.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr></table>
<p>
<div>
<pre>Created <span class=""><a href="attachment.cgi?id=24335" name="attach_24335" title="Simple ITT collector">attachment 24335</a> <a href="attachment.cgi?id=24335&action=edit" title="Simple ITT collector">[details]</a></span>
Simple ITT collector
Attempt to profile OpenMP application via ITT API (e.g. using VTune) leads to
crash within OpenMP runtime.
Steps to reproduce:
1) compile simple ITT collector (attached ittcollector.cpp):
g++ -std=c++11 -fPIC -g ./ittcollector.cpp -I <path to
llvm-project>/openmp/runtime/src/thirdparty/ittnotify/ -o libittc.so -shared
-ldl
2) compile the following OpenMP workload:
$ cat test.c
#include <stdio.h>
int main() {
#pragma omp parallel
{
printf("Hello!\n");
}
}
$ clang test.c -fopenmp -o test
3) run workload this way:
INTEL_LIBITTNOTIFY64=<absolute path>/libittc.so ./test
...
Hello!
Hello!
Hello!
Segmentation fault (core dumped)
Stack of crash:
Program received signal SIGSEGV, Segmentation fault.
0x000003fff7e74640 in __kmp_itt_frame_submit (gtid=0, begin=0, end=0,
imbalance=0, loc=0x400848, team_size=96, region=0)
at /home/vslobods/llvm-project-main/openmp/runtime/src/kmp_itt.inl:287
287 loc->reserved_2 |= (frm + 1) << 16; // save "new" value
Missing separate debuginfos, use: debuginfo-install glibc-2.17-260.el7.aarch64
(gdb) bt
#0 0x000003fff7e74640 in __kmp_itt_frame_submit (gtid=0, begin=0, end=0,
imbalance=0, loc=0x400848, team_size=96, region=0)
at /home/vslobods/llvm-project-main/openmp/runtime/src/kmp_itt.inl:287
#1 0x000003fff7ebba4c in __kmp_join_barrier (gtid=0) at
/home/vslobods/llvm-project-main/openmp/runtime/src/kmp_barrier.cpp:1874
#2 0x000003fff7e8d1b8 in __kmp_internal_join (id=0x400848, gtid=0,
team=0x44bc40)
at /home/vslobods/llvm-project-main/openmp/runtime/src/kmp_runtime.cpp:7468
#3 0x000003fff7e80878 in __kmp_join_call (loc=0x400848, gtid=0,
fork_context=fork_context_intel, exit_teams=0)
at /home/vslobods/llvm-project-main/openmp/runtime/src/kmp_runtime.cpp:2368
#4 0x000003fff7e6c120 in __kmpc_fork_call (loc=0x400848, argc=0,
microtask=0x40075c <.omp_outlined.>)
at /home/vslobods/llvm-project-main/openmp/runtime/src/kmp_csupport.cpp:314
#5 0x000000000040074c in main ()
It fails on attempt to write to loc->reserved_2 which resides in read-only
segment.
This is a regression in LLVM 11 (LLVM 10 doesn't have this issue) which still
resides within LLVM 12. The regression was introduced by the following commit:
<a href="https://github.com/llvm/llvm-project/commit/9f4a92a4349ff1794379b706a4851c678899d5d2">https://github.com/llvm/llvm-project/commit/9f4a92a4349ff1794379b706a4851c678899d5d2</a></pre>
</div>
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