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Memory ordering in pthread_mutex_{,timed}lock.

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All commits should have happened before the mutex lock is taken.
Therefore use the _rel variant of the cmpxchg atomic op.
This commit is contained in:
Ulrich Drepper 2009-07-26 13:00:04 -07:00
parent aa7492d20e
commit 7b7f43bed1
3 changed files with 19 additions and 12 deletions
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7
nptl/ChangeLog
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@ -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.

12
nptl/pthread_mutex_lock.c
View File

@ -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);
}

12
nptl/pthread_mutex_timedlock.c
View File

@ -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);
}