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o The mutex locking functions aren't normally cancellation points. But,

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we still have to DTRT when an asynchronously cancellable thread is
  cancelled while waiting for a mutex.
o While dequeueing a waiting mutex don't skip a thread if it has
  a cancel pending. Only skip it if it is also async cancellable.
This commit is contained in:
mtm 2004-03-26 14:47:54 +00:00
parent 8d2a2db80c
commit 194cc11a54
1 changed files with 12 additions and 3 deletions
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15
lib/libthr/thread/thr_mutex.c
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@ -324,7 +324,6 @@ mutex_lock_common(pthread_mutex_t * mutex, int nonblock,
PTHREAD_ASSERT(((*mutex)->m_protocol >= PTHREAD_PRIO_NONE &&
(*mutex)->m_protocol <= PTHREAD_PRIO_PROTECT),
"Invalid mutex protocol");
pthread_testcancel();
_SPINLOCK(&(*mutex)->lock);
/*
@ -418,7 +417,6 @@ mutex_lock_common(pthread_mutex_t * mutex, int nonblock,
_thread_critical_exit(curthread);
out:
_SPINUNLOCK(&(*mutex)->lock);
pthread_testcancel();
return (error);
}
@ -771,7 +769,10 @@ mutex_queue_deq(pthread_mutex_t mutex)
* Only exit the loop if the thread hasn't been
* cancelled.
*/
if ((pthread->cancelflags & PTHREAD_CANCELLING) == 0 &&
if (((pthread->cancelflags & PTHREAD_CANCELLING) == 0 ||
(pthread->cancelflags & PTHREAD_CANCEL_DISABLE) != 0 ||
((pthread->cancelflags & PTHREAD_CANCELLING) != 0 &&
(pthread->cancelflags & PTHREAD_CANCEL_ASYNCHRONOUS) == 0)) &&
pthread->state == PS_MUTEX_WAIT)
break;
else
@ -887,6 +888,14 @@ get_mcontested(pthread_mutex_t mutexp, const struct timespec *abstime)
_thread_critical_enter(curthread);
mutex_queue_enq(mutexp, curthread);
do {
if ((curthread->cancelflags & PTHREAD_CANCEL_ASYNCHRONOUS) != 0 &&
(curthread->cancelflags & PTHREAD_CANCEL_DISABLE) == 0 &&
(curthread->cancelflags & PTHREAD_CANCELLING) != 0) {
mutex_queue_remove(mutexp, curthread);
_thread_critical_exit(curthread);
_SPINUNLOCK(&mutexp->lock);
pthread_testcancel();
}
PTHREAD_SET_STATE(curthread, PS_MUTEX_WAIT);
curthread->data.mutex = mutexp;
_thread_critical_exit(curthread);