CVS commit: src/lib/libpthread

["Mindaugas Rasiukevicius" <rmind%netbsd.org@localhost>]

Module Name:    src
Committed By:   rmind
Date:           Mon Feb  3 15:51:01 UTC 2014

Modified Files:
        src/lib/libpthread: pthread_mutex.c

Log Message:
pthread__mutex_lock_slow: fix the handling of a potential race with the
non-interlocked CAS in the fast unlock path -- it is unsafe to test for
the waiters-bit while the owner thread is running, we have to spin for
the owner or its state change to be sure about the presence of the bit.
Split off the logic into the pthread__mutex_setwaiters() routine.

This is a partial fix to the named lockup problem (also see PR/44756).
It seems there is another race which can be reproduced on faster CPUs.


To generate a diff of this commit:
cvs rdiff -u -r1.58 -r1.59 src/lib/libpthread/pthread_mutex.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.