[PATCH] Fix harmless access to uninitialized memory in ri_triggers.c.

From: Andres Freund <andres@anarazel.de>

When cache invalidations arrive while ri_LoadConstraintInfo() is busy
filling a new cache entry, InvalidateConstraintCacheCallBack()
compares the - not yet initialized - oidHashValue field with the
to-be-invalidated hash value. To fix check whether the entry is
already marked as invalid.
---src/backend/utils/adt/ri_triggers.c | 3 ++-1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/backend/utils/adt/ri_triggers.c b/src/backend/utils/adt/ri_triggers.c
index d30847b..e4d7b2c 100644
--- a/src/backend/utils/adt/ri_triggers.c
+++ b/src/backend/utils/adt/ri_triggers.c
@@ -2934,7 +2934,8 @@ InvalidateConstraintCacheCallBack(Datum arg, int cacheid, uint32 hashvalue)
hash_seq_init(&status,ri_constraint_cache);    while ((hentry = (RI_ConstraintInfo *) hash_seq_search(&status)) !=
NULL)   {
 
-        if (hashvalue == 0 || hentry->oidHashValue == hashvalue)
+        if (hentry->valid &&
+            (hashvalue == 0 || hentry->oidHashValue == hashvalue))            hentry->valid = false;    }}
-- 
1.8.5.rc2.dirty