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Fix race condition in ConditionVariablePrepareToSleep.

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Thomas Munro
This commit is contained in:
Robert Haas 2017-02-09 14:42:32 -05:00
parent fc8219dc54
commit 3f3d60d3bb
1 changed files with 6 additions and 3 deletions
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9
src/backend/storage/lmgr/condition_variable.c
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@ -71,14 +71,17 @@ ConditionVariablePrepareToSleep(ConditionVariable *cv)
&MyProc->procLatch, NULL); &MyProc->procLatch, NULL);
} }
/*
* Reset my latch before adding myself to the queue and before entering
* the caller's predicate loop.
*/
ResetLatch(&MyProc->procLatch);
/* Add myself to the wait queue. */ /* Add myself to the wait queue. */
SpinLockAcquire(&cv->mutex); SpinLockAcquire(&cv->mutex);
if (!proclist_contains(&cv->wakeup, pgprocno, cvWaitLink)) if (!proclist_contains(&cv->wakeup, pgprocno, cvWaitLink))
proclist_push_tail(&cv->wakeup, pgprocno, cvWaitLink); proclist_push_tail(&cv->wakeup, pgprocno, cvWaitLink);
SpinLockRelease(&cv->mutex); SpinLockRelease(&cv->mutex);
/* Reset my latch before entering the caller's predicate loop. */
ResetLatch(&MyProc->procLatch);
} }
/*-------------------------------------------------------------------------- /*--------------------------------------------------------------------------