PR/44756 CVS commit: src/lib/libpthread

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

The following reply was made to PR lib/44756; it has been noted by GNATS.

From: "Mindaugas Rasiukevicius" <rmind%netbsd.org@localhost>
To: gnats-bugs%gnats.NetBSD.org@localhost
Cc: 
Subject: PR/44756 CVS commit: src/lib/libpthread
Date: Mon, 3 Feb 2014 15:51:01 +0000

 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.