From: Robert Haas <rhaas@postgresql.org>
Date: Mon, 31 Mar 2014 18:32:12 +0000 (-0400)
Subject: Mark FastPathStrongRelationLocks volatile.
X-Git-Tag: REL9_4_BETA1~249
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=4bc15a8bfbc7856bc3426dc9ab99567eebbb64d3;p=postgresql

Mark FastPathStrongRelationLocks volatile.

Otherwise, the compiler might decide to move modifications to data
within this structure outside the enclosing SpinLockAcquire /
SpinLockRelease pair, leading to shared memory corruption.

This may or may not explain a recent lmgr-related buildfarm failure
on prairiedog, but it needs to be fixed either way.
---

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 6335129ac2..fd6cd0647e 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -238,7 +238,7 @@ typedef struct
 	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
 } FastPathStrongRelationLockData;
 
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks;
 
 
 /*