Author: rstone
Date: Fri Nov 11 02:10:24 2011
New Revision: 227438
URL: http://svn.freebsd.org/changeset/base/227438
Log:
MFC 220888
r179417 introduced a bug into pthread_once(). Previously pthread_once()
used a global pthread_mutex_t for synchronization. r179417 replaced that
with an implementation that directly used atomic instructions and thr_*
syscalls to synchronize callers to pthread_once. However, calling
pthread_mutex_lock on the global mutex implicitly ensured that
_thr_check_init() had been called but with r179417 this was no longer
guaranteed. This meant that if you were unlucky enough to have your first
call into libthr be a call to pthread_once(), you would segfault when
trying to access the pointer returned by _get_curthread().
The fix is to explicitly call _thr_check_init() from pthread_once().
Modified:
stable/8/lib/libthr/thread/thr_once.c
Directory Properties:
stable/8/lib/libthr/ (props changed)
Modified: stable/8/lib/libthr/thread/thr_once.c
==============================================================================
--- stable/8/lib/libthr/thread/thr_once.c Fri Nov 11 02:02:55 2011
(r227437)
+++ stable/8/lib/libthr/thread/thr_once.c Fri Nov 11 02:10:24 2011
(r227438)
@@ -64,6 +64,8 @@ _pthread_once(pthread_once_t *once_contr
struct pthread *curthread;
int state;
+ _thr_check_init();
+
for (;;) {
state = once_control->state;
if (state == ONCE_DONE)
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