mirror of
https://sourceware.org/git/glibc.git
synced 2024-11-14 17:11:06 +00:00
8f630cca5c
lll_unlock() will be called again if it goes to "wake_all" in
pthread_cond_broadcast(). This may make another thread which is
waiting for lock in pthread_cond_timedwait() unlock. So there are
more than one threads get the lock, it will break the shared data.
It's introduced by commit 8313cb997d2d("FUTEX_*_REQUEUE_PI support for
non-x86 code")
95 lines
2.9 KiB
C
95 lines
2.9 KiB
C
/* Copyright (C) 2003-2014 Free Software Foundation, Inc.
|
|
This file is part of the GNU C Library.
|
|
Contributed by Martin Schwidefsky <schwidefsky@de.ibm.com>, 2003.
|
|
|
|
The GNU C Library is free software; you can redistribute it and/or
|
|
modify it under the terms of the GNU Lesser General Public
|
|
License as published by the Free Software Foundation; either
|
|
version 2.1 of the License, or (at your option) any later version.
|
|
|
|
The GNU C Library is distributed in the hope that it will be useful,
|
|
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
Lesser General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Lesser General Public
|
|
License along with the GNU C Library; if not, see
|
|
<http://www.gnu.org/licenses/>. */
|
|
|
|
#include <endian.h>
|
|
#include <errno.h>
|
|
#include <sysdep.h>
|
|
#include <lowlevellock.h>
|
|
#include <pthread.h>
|
|
#include <pthreadP.h>
|
|
#include <stap-probe.h>
|
|
|
|
#include <shlib-compat.h>
|
|
#include <kernel-features.h>
|
|
|
|
|
|
int
|
|
__pthread_cond_broadcast (cond)
|
|
pthread_cond_t *cond;
|
|
{
|
|
LIBC_PROBE (cond_broadcast, 1, cond);
|
|
|
|
int pshared = (cond->__data.__mutex == (void *) ~0l)
|
|
? LLL_SHARED : LLL_PRIVATE;
|
|
/* Make sure we are alone. */
|
|
lll_lock (cond->__data.__lock, pshared);
|
|
|
|
/* Are there any waiters to be woken? */
|
|
if (cond->__data.__total_seq > cond->__data.__wakeup_seq)
|
|
{
|
|
/* Yes. Mark them all as woken. */
|
|
cond->__data.__wakeup_seq = cond->__data.__total_seq;
|
|
cond->__data.__woken_seq = cond->__data.__total_seq;
|
|
cond->__data.__futex = (unsigned int) cond->__data.__total_seq * 2;
|
|
int futex_val = cond->__data.__futex;
|
|
/* Signal that a broadcast happened. */
|
|
++cond->__data.__broadcast_seq;
|
|
|
|
/* We are done. */
|
|
lll_unlock (cond->__data.__lock, pshared);
|
|
|
|
/* Wake everybody. */
|
|
pthread_mutex_t *mut = (pthread_mutex_t *) cond->__data.__mutex;
|
|
|
|
/* Do not use requeue for pshared condvars. */
|
|
if (mut == (void *) ~0l
|
|
|| PTHREAD_MUTEX_PSHARED (mut) & PTHREAD_MUTEX_PSHARED_BIT)
|
|
goto wake_all;
|
|
|
|
#if (defined lll_futex_cmp_requeue_pi \
|
|
&& defined __ASSUME_REQUEUE_PI)
|
|
if (USE_REQUEUE_PI (mut))
|
|
{
|
|
if (lll_futex_cmp_requeue_pi (&cond->__data.__futex, 1, INT_MAX,
|
|
&mut->__data.__lock, futex_val,
|
|
LLL_PRIVATE) == 0)
|
|
return 0;
|
|
}
|
|
else
|
|
#endif
|
|
/* lll_futex_requeue returns 0 for success and non-zero
|
|
for errors. */
|
|
if (!__builtin_expect (lll_futex_requeue (&cond->__data.__futex, 1,
|
|
INT_MAX, &mut->__data.__lock,
|
|
futex_val, LLL_PRIVATE), 0))
|
|
return 0;
|
|
|
|
wake_all:
|
|
lll_futex_wake (&cond->__data.__futex, INT_MAX, pshared);
|
|
return 0;
|
|
}
|
|
|
|
/* We are done. */
|
|
lll_unlock (cond->__data.__lock, pshared);
|
|
|
|
return 0;
|
|
}
|
|
|
|
versioned_symbol (libpthread, __pthread_cond_broadcast, pthread_cond_broadcast,
|
|
GLIBC_2_3_2);
|