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authorUlrich Drepper <drepper@redhat.com>2000-09-27 00:14:27 +0000
committerUlrich Drepper <drepper@redhat.com>2000-09-27 00:14:27 +0000
commit75dbc100bf903f908c4e5e90783307cf445b19db (patch)
treec92289288e27adeeb6fb0a7d728e2c42db5c82a7 /linuxthreads/spinlock.h
parentb0557314bc23ed0020cc673cabd540518ab3ed16 (diff)
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Update.
2000-09-26 Ulrich Drepper <drepper@redhat.com> * sysdeps/unix/sysv/linux/i386/bits/time.h: Remove CLOCK_MONOTONIC.
Diffstat (limited to 'linuxthreads/spinlock.h')
-rw-r--r--linuxthreads/spinlock.h23
1 files changed, 17 insertions, 6 deletions
diff --git a/linuxthreads/spinlock.h b/linuxthreads/spinlock.h
index c194d79..2d3e9bf 100644
--- a/linuxthreads/spinlock.h
+++ b/linuxthreads/spinlock.h
@@ -212,11 +212,22 @@ static inline long atomic_decrement(struct pthread_atomic *pa)
static inline void
-__pthread_set_own_extricate_if(pthread_descr self, pthread_extricate_if *peif)
+__pthread_set_own_extricate_if (pthread_descr self, pthread_extricate_if *peif)
{
- /* The locks here are not ensuring an atomic update of the p_extricate
- pointer. They protect users of the pointer from using stale memory. */
- __pthread_lock(THREAD_GETMEM(self, p_lock), self);
- THREAD_SETMEM(self, p_extricate, peif);
- __pthread_unlock(THREAD_GETMEM (self, p_lock));
+ /* Only store a non-null peif if the thread has cancellation enabled.
+ Otherwise pthread_cancel will unconditionally call the extricate handler,
+ and restart the thread giving rise to forbidden spurious wakeups. */
+ if (peif == NULL
+ || THREAD_GETMEM(self, p_cancelstate) == PTHREAD_CANCEL_ENABLE)
+ {
+ /* If we are removing the extricate interface, we need to synchronize
+ against pthread_cancel so that it does not continue with a pointer
+ to a deallocated pthread_extricate_if struct! The thread lock
+ is (ab)used for this synchronization purpose. */
+ if (peif == NULL)
+ __pthread_lock (THREAD_GETMEM(self, p_lock), self);
+ THREAD_SETMEM(self, p_extricate, peif);
+ if (peif == NULL)
+ __pthread_unlock (THREAD_GETMEM(self, p_lock));
+ }
}