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sched/pthread/pthread_condwait.c: Fix cancellation bug.

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Now that nxsem_wait_uninterruptible() returns an error when the thread is canceled, new logic is being executed.  This revealed an existing error in pthread_cond_wait().  The nature of the error is as follows:

* pthread_cond_wait() must atomically (1) release the mutex, (2) wait on the condition, and (3) re-establish the mutex.  Errors can occur on any of these steps.  In this case the ECANCELED error was (very correctly) reported by nxsem_wait_uninterruptible().

* However, logic in step (3) had a bug; it re-acquired the mutex, but then a bug in existing logic cause the mutex to be improperly initialized.  Essentially, the wrong error status value was being testing.  This resulted in a nonsequitar and errors reported by the OS test.

This problem was found by apps/testing/ostest/pthread_cleanup.c
This commit is contained in:
Gregory Nutt 2020-04-05 14:52:23 -06:00 committed by Abdelatif Guettouche
parent 679b4fbee2
commit 64b398f4c6
1 changed files with 23 additions and 31 deletions
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54
sched/pthread/pthread_condwait.c
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@ -1,35 +1,20 @@
/****************************************************************************
* sched/pthread/pthread_condwait.c
*
* Copyright (C) 2007-2009, 2012, 2016 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* http://www.apache.org/licenses/LICENSE-2.0
*
* 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 NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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
* COPYRIGHT OWNER 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.
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
@ -101,9 +86,11 @@ int pthread_cond_wait(FAR pthread_cond_t *cond, FAR pthread_mutex_t *mutex)
sched_lock();
mutex->pid = -1;
ret = pthread_mutex_give(mutex);
ret = pthread_mutex_give(mutex);
/* Take the semaphore */
/* Take the semaphore. This may be awakened only be a signal (EINTR)
* or if the thread is canceled (ECANCELED)
*/
status = pthread_sem_take((FAR sem_t *)&cond->sem, NULL, false);
if (ret == OK)
@ -132,11 +119,16 @@ int pthread_cond_wait(FAR pthread_cond_t *cond, FAR pthread_mutex_t *mutex)
ret = status;
}
/* Was all of the above successful? */
/* Did we get the mutex? */
if (ret == OK)
if (status == OK)
{
/* Yes.. Then initialize it properly */
mutex->pid = getpid();
#ifdef CONFIG_PTHREAD_MUTEX_TYPES
mutex->nlocks = 1;
#endif
}
}