svn commit: r233103 - head/lib/libthr/thread
David Xu
davidxu at FreeBSD.org
Sun Mar 18 00:22:30 UTC 2012
Author: davidxu
Date: Sun Mar 18 00:22:29 2012
New Revision: 233103
URL: http://svn.freebsd.org/changeset/base/233103
Log:
Some software think a mutex can be destroyed after it owned it, for
example, it uses a serialization point like following:
pthread_mutex_lock(&mutex);
pthread_mutex_unlock(&mutex);
pthread_mutex_destroy(&muetx);
They think a previous lock holder should have already left the mutex and
is no longer referencing it, so they destroy it. To be maximum compatible
with such code, we use IA64 version to unlock the mutex in kernel, remove
the two steps unlocking code.
Modified:
head/lib/libthr/thread/thr_umtx.c
Modified: head/lib/libthr/thread/thr_umtx.c
==============================================================================
--- head/lib/libthr/thread/thr_umtx.c Sat Mar 17 23:55:18 2012 (r233102)
+++ head/lib/libthr/thread/thr_umtx.c Sun Mar 18 00:22:29 2012 (r233103)
@@ -154,13 +154,6 @@ __thr_umutex_timedlock(struct umutex *mt
int
__thr_umutex_unlock(struct umutex *mtx, uint32_t id)
{
-#ifndef __ia64__
- /* XXX this logic has a race-condition on ia64. */
- if ((mtx->m_flags & (UMUTEX_PRIO_PROTECT | UMUTEX_PRIO_INHERIT)) == 0) {
- atomic_cmpset_rel_32(&mtx->m_owner, id | UMUTEX_CONTESTED, UMUTEX_CONTESTED);
- return _umtx_op_err(mtx, UMTX_OP_MUTEX_WAKE, 0, 0, 0);
- }
-#endif /* __ia64__ */
return _umtx_op_err(mtx, UMTX_OP_MUTEX_UNLOCK, 0, 0, 0);
}
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