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<base href="https://llvm.org/bugs/" />
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<body><table border="1" cellspacing="0" cellpadding="8">
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - Tasking Deadlock or Segfault in OpenMP Runtime on Power8"
href="https://llvm.org/bugs/show_bug.cgi?id=27167">27167</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>Tasking Deadlock or Segfault in OpenMP Runtime on Power8
</td>
</tr>
<tr>
<th>Product</th>
<td>OpenMP
</td>
</tr>
<tr>
<th>Version</th>
<td>unspecified
</td>
</tr>
<tr>
<th>Hardware</th>
<td>Other
</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>matt.davis@pgroup.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr>
<tr>
<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>Created <span class=""><a href="attachment.cgi?id=16142" name="attach_16142" title="Test case that hangs">attachment 16142</a> <a href="attachment.cgi?id=16142&action=edit" title="Test case that hangs">[details]</a></span>
Test case that hangs
I am running into a runtime hang when executing the attached OpenMP test case
with clang 3.8.0
I have a feeling this has to do with tasking. Additionally, one of our other
engineers here can get this to segfault, but I have not been able to. I
usually have to execute this test in a for-loop:
for i in `seq 1000`; do ./a.out; done
Environment:
OMP_NUM_THREADS=2
Build line:
clang -fopenmp omp_task_lock.c
Clang
clang version 3.8.0
Target: powerpc64le-unknown-linux-gnu
Thread model: posix
InstalledDir: /home/sw/thirdparty/llvm/linuxpower/3.8-openmp/bin
Found candidate GCC installation: /usr/lib/gcc/powerpc64le-linux-gnu/4.8
Found candidate GCC installation: /usr/lib/gcc/powerpc64le-linux-gnu/4.8.4
Found candidate GCC installation: /usr/lib/gcc/powerpc64le-linux-gnu/4.9
Found candidate GCC installation: /usr/lib/gcc/powerpc64le-linux-gnu/4.9.3
Selected GCC installation: /usr/lib/gcc/powerpc64le-linux-gnu/4.8
Candidate multilib: .;@m64
Selected multilib: .;@m64
Found CUDA installation: /usr/local/cuda
System:
Linux tuleta14 3.16.0-62-generic #83~14.04.1-Ubuntu SMP Fri Feb 26 22:52:11 UTC
2016 ppc64le ppc64le ppc64le GNU/Linux
When I get the runtime to hang I get the following stack trace:
(gdb) info threads
Id Target Id Frame
3 Thread 0x3fff803af1a0 (LWP 148370) "a.out" 0x00003fff8059eb74 in
__pthread_cond_timedwait (cond=0x3fff8067e800 <__kmp_wait_cv>,
mutex=0x3fff8067c080 <__kmp_wait_mx>, abstime=0x3fff803ae600) at
pthread_cond_timedwait.c:199
2 Thread 0x3fff8037f2a0 (LWP 148371) "a.out" 0x00003fff80615128 in
__kmp_execute_tasks_64 () from /3.8-openmp/lib/libomp.so
* 1 Thread 0x3fff806843f0 (LWP 148369) "a.out" 0x00003fff806144dc in
__kmp_execute_tasks_32 () from /3.8-openmp/lib/libomp.so
(gdb) bt
#0 0x00003fff806144dc in __kmp_execute_tasks_32 () from
/3.8-openmp/lib/libomp.so
#1 0x00003fff80617400 in __kmp_task_team_wait () from
/3.8-openmp/lib/libomp.so
#2 0x00003fff80635984 in __kmp_barrier () from /3.8-openmp/lib/libomp.so
#3 0x00003fff805f31ac in __kmpc_barrier () from /3.8-openmp/lib/libomp.so
#4 0x0000000010000c38 in .omp_outlined. ()
#5 0x00003fff806229d8 in __kmp_invoke_microtask () from
/3.8-openmp/lib/libomp.so
#6 0x00003fff806021ec in __kmp_invoke_task_func () from
/3.8-openmp/lib/libomp.so
#7 0x00003fff806031e4 in __kmp_fork_call () from /3.8-openmp/lib/libomp.so
#8 0x00003fff805f29f4 in __kmpc_fork_call () from /3.8-openmp/lib/libomp.so
#9 0x0000000010000a44 in test_omp_task_private ()
#10 0x0000000010000f18 in test ()
#11 0x0000000010000e68 in main ()</pre>
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