Cancel CV sleep during subtransaction abort.

robertmhaas · robertmhaas · commit 59d1e2b95a82 · 2017-12-21T09:24:30.000-05:00
Generally, error recovery paths that need to do things like LWLockReleaseAll and pgstat_report_wait_end also need to call ConditionVariableCancelSleep, but AbortSubTransaction was missed. Since subtransaction abort might destroy up the DSM segment that contains the ConditionVariable stored in cv_sleep_target, this can result in a crash for anything using condition variables. Reported and diagnosed by Andres Freund. Discussion: http://postgr.es/m/20171221110048.rxk6464azzl5t2fi@alap3.anarazel.de
diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c
@@ -4717,6 +4717,9 @@ AbortSubTransaction(void)
 	/* Reset WAL record construction state */
 	XLogResetInsertion();
 
+	/* Cancel condition variable sleep */
+	ConditionVariableCancelSleep();
+
 	/*
 	 * Also clean up any open wait for lock, since the lock manager will choke
 	 * if we try to wait for another lock before doing this.
