From: Robert Haas <rhaas@postgresql.org>
Date: Thu, 21 Dec 2017 14:09:04 +0000 (-0500)
Subject: Cancel CV sleep during subtransaction abort.
X-Git-Tag: REL_11_BETA1~1046
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=59d1e2b95a826869e2789ffe01e9e552148eefde;p=postgresql

Cancel CV sleep during subtransaction abort.

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
index e93d740b21..d430e662e6 100644
--- 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.