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authorRich Felker <dalias@aerifal.cx>2011-08-02 20:31:15 -0400
committerRich Felker <dalias@aerifal.cx>2011-08-02 20:31:15 -0400
commitc68de0be2fb649f91b31080224fb6e48084eaaee (patch)
treed9495283490f37833ca6e32f4b6876ca10ac06eb /src/thread/pthread_mutex_lock.c
parent344ea148852ed02f280cb92f8fc1611529d60448 (diff)
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avoid accessing mutex memory after atomic unlock
this change is needed to fix a race condition and ensure that it's possible to unlock and destroy or unmap the mutex as soon as pthread_mutex_lock succeeds. POSIX explicitly gives such an example in the rationale and requires an implementation to allow such usage.
Diffstat (limited to 'src/thread/pthread_mutex_lock.c')
-rw-r--r--src/thread/pthread_mutex_lock.c14
1 files changed, 1 insertions, 13 deletions
diff --git a/src/thread/pthread_mutex_lock.c b/src/thread/pthread_mutex_lock.c
index 99c15bd8..2b4f3a73 100644
--- a/src/thread/pthread_mutex_lock.c
+++ b/src/thread/pthread_mutex_lock.c
@@ -2,17 +2,5 @@
int pthread_mutex_lock(pthread_mutex_t *m)
{
- int r;
-
- if (m->_m_type == PTHREAD_MUTEX_NORMAL && !a_swap(&m->_m_lock, EBUSY))
- return 0;
-
- while ((r=pthread_mutex_trylock(m)) == EBUSY) {
- if (!(r=m->_m_lock) || (r&0x40000000)) continue;
- if ((m->_m_type&3) == PTHREAD_MUTEX_ERRORCHECK
- && (r&0x1fffffff) == pthread_self()->tid)
- return EDEADLK;
- __wait(&m->_m_lock, &m->_m_waiters, r, 0);
- }
- return r;
+ return pthread_mutex_timedlock(m, 0);
}