It's not OK to do that without calling CHECK_FOR_INTERRUPTS().
Let the next wait loop deal with it, following the usual pattern.
One consequence of this bug was that a SIGTERM delivered in a very
narrow timing window could leave a parallel worker process waiting
forever for a condition variable that will never be signaled, after
an error was raised in other process.
The code is a bit different in the stable branches due to commit
1321509f, making problems less likely there. No back-patch for now,
but we may finish up deciding to make a similar change after more
discussion.
Author: Thomas Munro
Reviewed-by: Shawn Debnath
Reported-by: Tomas Vondra
Discussion: https://postgr.es/m/CA%2BhUKGJOm8zZHjVA8svoNT3tHY0XdqmaC_kHitmgXDQM49m1dA%40mail.gmail.com
index 0e7f07961eedcadcab9ec64412ca7c7814042933..37b6a4eecdb68a4a97de33a2c225cc673abec550 100644 (file)
@@ -93,12 +93,6 @@ ConditionVariablePrepareToSleep(ConditionVariable *cv)
/* Record the condition variable on which we will sleep. */
cv_sleep_target = cv;
- /*
- * Reset my latch before adding myself to the queue, to ensure that we
- * don't miss a wakeup that occurs immediately.
- */
- ResetLatch(MyLatch);
-
/* Add myself to the wait queue. */
SpinLockAcquire(&cv->mutex);
proclist_push_tail(&cv->wakeup, pgprocno, cvWaitLink);