freebsd-skq/lib/libthr/thread/thr_resume_np.c
kib 070c6cd670 Do not leak THR_FLAGS_SUSPENDED from the previous suspend/resume
cycle.  The flag currently is cleared by the resumed thread.  If next
suspend request comes before the thread was able to clean the flag, in
which case suspender skip the thread.

Instead, clear the THR_FLAGS_SUSPEND flag in resume_common(), we do
not care how much code was executed in the resumed thread when the
pthread_resume_*np(s) functions returned.

PR:	209233
Reported by:	Lawrence Esswood <le277@cam.ac.uk>
MFC after:	1 week
2016-05-05 10:20:22 +00:00

98 lines
3.1 KiB
C

/*
* Copyright (c) 1995 John Birrell <jb@cimlogic.com.au>.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the author nor the names of any co-contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "namespace.h"
#include <errno.h>
#include <pthread.h>
#include <pthread_np.h>
#include "un-namespace.h"
#include "thr_private.h"
__weak_reference(_pthread_resume_np, pthread_resume_np);
__weak_reference(_pthread_resume_all_np, pthread_resume_all_np);
static void resume_common(struct pthread *thread);
/* Resume a thread: */
int
_pthread_resume_np(pthread_t thread)
{
struct pthread *curthread = _get_curthread();
int ret;
/* Add a reference to the thread: */
if ((ret = _thr_find_thread(curthread, thread, /*include dead*/0)) == 0) {
/* Lock the threads scheduling queue: */
resume_common(thread);
THR_THREAD_UNLOCK(curthread, thread);
}
return (ret);
}
void
_pthread_resume_all_np(void)
{
struct pthread *curthread = _get_curthread();
struct pthread *thread;
int old_nocancel;
old_nocancel = curthread->no_cancel;
curthread->no_cancel = 1;
_thr_suspend_all_lock(curthread);
/* Take the thread list lock: */
THREAD_LIST_RDLOCK(curthread);
TAILQ_FOREACH(thread, &_thread_list, tle) {
if (thread != curthread) {
THR_THREAD_LOCK(curthread, thread);
resume_common(thread);
THR_THREAD_UNLOCK(curthread, thread);
}
}
/* Release the thread list lock: */
THREAD_LIST_UNLOCK(curthread);
_thr_suspend_all_unlock(curthread);
curthread->no_cancel = old_nocancel;
_thr_testcancel(curthread);
}
static void
resume_common(struct pthread *thread)
{
/* Clear the suspend flag: */
thread->flags &= ~(THR_FLAGS_NEED_SUSPEND | THR_FLAGS_SUSPENDED);
thread->cycle++;
_thr_umtx_wake(&thread->cycle, 1, 0);
}