Date: Wed, 20 Apr 2011 14:19:34 +0000 (UTC) From: Ryan Stone <rstone@FreeBSD.org> To: cvs-src-old@freebsd.org Subject: cvs commit: src/lib/libthr/thread thr_once.c Message-ID: <201104201419.p3KEJfOk016008@repoman.freebsd.org>
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rstone 2011-04-20 14:19:34 UTC
FreeBSD src repository
Modified files:
lib/libthr/thread thr_once.c
Log:
SVN rev 220888 on 2011-04-20 14:19:34Z by rstone
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().
Reviewed by: davidxu
Approved by: emaste (mentor)
MFC after: 1 week
Revision Changes Path
1.8 +2 -0 src/lib/libthr/thread/thr_once.c
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