[Valgrind-users] Helgrind 3.9.0: false positive with pthread_mutex_destroy

[Saurabh T <sa...@ho...>]

Helgrind seems to be reporting false positive data race when pthread_mutex_destroy is called in a different thread from pthread_mutex_unlock. Unfortunately I cannot make a test case, sorry. But here's the relevant output:

==15996== Possible data race during read of size 1 at 0x4DA7F90 by thread #1
==15996== Locks held: none
==15996==    at 0x4A08D79: my_memcmp (hg_intercepts.c:165)
==15996==    by 0x4A0906F: pthread_mutex_destroy (hg_intercepts.c:473)
<snip>
==15996==
==15996== This conflicts with a previous write of size 4 by thread #52
==15996== Locks held: none
==15996==    at 0x34EF80D5E2: __lll_unlock_wake (in /lib64/libpthread-2.5.so)
==15996==    by 0x34EF80A0E6: _L_unlock_766 (in /lib64/libpthread-2.5.so)
==15996==    by 0x34EF80A04C: pthread_mutex_unlock (in /lib64/libpthread-2.5.so)
==15996==    by 0x4A097E0: pthread_mutex_unlock (hg_intercepts.c:635)
<snip>
==15996==
==15996== Address 0x4DA7F90 is 0 bytes inside a block of size 40 alloc'd
==15996==    at 0x4A08BE5: operator new(unsigned long) (vg_replace_malloc.c:319)
<snip>

This was not a problem with 3.8.1 so appears to be a regression or new bug.

saurabh