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authorUlrich Drepper <drepper@redhat.com>2009-07-26 13:00:04 -0700
committerUlrich Drepper <drepper@redhat.com>2009-07-26 13:00:04 -0700
commit7b7f43bed134db6a0da34282fffcbf0af10d4613 (patch)
tree51943739e388fb9bba90e9a872747d5d84bf5820
parentaa7492d20e5a2cef54dab7b41f534048b3eca479 (diff)
Memory ordering in pthread_mutex_{,timed}lock.
All commits should have happened before the mutex lock is taken. Therefore use the _rel variant of the cmpxchg atomic op.
-rw-r--r--nptl/ChangeLog7
-rw-r--r--nptl/pthread_mutex_lock.c12
-rw-r--r--nptl/pthread_mutex_timedlock.c12
3 files changed, 19 insertions, 12 deletions
diff --git a/nptl/ChangeLog b/nptl/ChangeLog
index cb9ec53cd1..222112161a 100644
--- a/nptl/ChangeLog
+++ b/nptl/ChangeLog
@@ -1,3 +1,10 @@
+2009-07-26 Ulrich Drepper <drepper@redhat.com>
+
+ [BZ #10418]
+ * pthread_mutex_lock.c (pthread_mutex_lock): Use _rel instead of of
+ _acq variants of cmpxchg.
+ * pthread_mutex_timedlock.c (pthread_mutex_timedlock): Likewise.
+
2009-07-23 Ulrich Drepper <drepper@redhat.com>
* sysdeps/x86_64/configure.in: New file.
diff --git a/nptl/pthread_mutex_lock.c b/nptl/pthread_mutex_lock.c
index 406e588fdb..a0ff881faf 100644
--- a/nptl/pthread_mutex_lock.c
+++ b/nptl/pthread_mutex_lock.c
@@ -1,4 +1,4 @@
-/* Copyright (C) 2002-2007, 2008 Free Software Foundation, Inc.
+/* Copyright (C) 2002-2007, 2008, 2009 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
@@ -160,7 +160,7 @@ __pthread_mutex_lock_full (pthread_mutex_t *mutex)
#endif
newval
- = atomic_compare_and_exchange_val_acq (&mutex->__data.__lock,
+ = atomic_compare_and_exchange_val_rel (&mutex->__data.__lock,
newval, oldval);
if (newval != oldval)
@@ -285,7 +285,7 @@ __pthread_mutex_lock_full (pthread_mutex_t *mutex)
#ifdef NO_INCR
newval |= FUTEX_WAITERS;
#endif
- oldval = atomic_compare_and_exchange_val_acq (&mutex->__data.__lock,
+ oldval = atomic_compare_and_exchange_val_rel (&mutex->__data.__lock,
newval, 0);
if (oldval != 0)
@@ -420,7 +420,7 @@ __pthread_mutex_lock_full (pthread_mutex_t *mutex)
oldprio = ceiling;
oldval
- = atomic_compare_and_exchange_val_acq (&mutex->__data.__lock,
+ = atomic_compare_and_exchange_val_rel (&mutex->__data.__lock,
#ifdef NO_INCR
ceilval | 2,
#else
@@ -434,7 +434,7 @@ __pthread_mutex_lock_full (pthread_mutex_t *mutex)
do
{
oldval
- = atomic_compare_and_exchange_val_acq (&mutex->__data.__lock,
+ = atomic_compare_and_exchange_val_rel (&mutex->__data.__lock,
ceilval | 2,
ceilval | 1);
@@ -445,7 +445,7 @@ __pthread_mutex_lock_full (pthread_mutex_t *mutex)
lll_futex_wait (&mutex->__data.__lock, ceilval | 2,
PTHREAD_MUTEX_PSHARED (mutex));
}
- while (atomic_compare_and_exchange_val_acq (&mutex->__data.__lock,
+ while (atomic_compare_and_exchange_val_rel (&mutex->__data.__lock,
ceilval | 2, ceilval)
!= ceilval);
}
diff --git a/nptl/pthread_mutex_timedlock.c b/nptl/pthread_mutex_timedlock.c
index 8d0db79d58..2c6ff114da 100644
--- a/nptl/pthread_mutex_timedlock.c
+++ b/nptl/pthread_mutex_timedlock.c
@@ -1,4 +1,4 @@
-/* Copyright (C) 2002-2007, 2008 Free Software Foundation, Inc.
+/* Copyright (C) 2002-2007, 2008, 2009 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
@@ -126,7 +126,7 @@ pthread_mutex_timedlock (mutex, abstime)
int newval = id | (oldval & FUTEX_WAITERS);
newval
- = atomic_compare_and_exchange_val_acq (&mutex->__data.__lock,
+ = atomic_compare_and_exchange_val_rel (&mutex->__data.__lock,
newval, oldval);
if (newval != oldval)
{
@@ -246,7 +246,7 @@ pthread_mutex_timedlock (mutex, abstime)
}
}
- oldval = atomic_compare_and_exchange_val_acq (&mutex->__data.__lock,
+ oldval = atomic_compare_and_exchange_val_rel (&mutex->__data.__lock,
id, 0);
if (oldval != 0)
@@ -404,7 +404,7 @@ pthread_mutex_timedlock (mutex, abstime)
oldprio = ceiling;
oldval
- = atomic_compare_and_exchange_val_acq (&mutex->__data.__lock,
+ = atomic_compare_and_exchange_val_rel (&mutex->__data.__lock,
ceilval | 1, ceilval);
if (oldval == ceilval)
@@ -413,7 +413,7 @@ pthread_mutex_timedlock (mutex, abstime)
do
{
oldval
- = atomic_compare_and_exchange_val_acq (&mutex->__data.__lock,
+ = atomic_compare_and_exchange_val_rel (&mutex->__data.__lock,
ceilval | 2,
ceilval | 1);
@@ -456,7 +456,7 @@ pthread_mutex_timedlock (mutex, abstime)
PTHREAD_MUTEX_PSHARED (mutex));
}
}
- while (atomic_compare_and_exchange_val_acq (&mutex->__data.__lock,
+ while (atomic_compare_and_exchange_val_rel (&mutex->__data.__lock,
ceilval | 2, ceilval)
!= ceilval);
}