From 478e0069fb8bc30d7e0c1a8fc390ed041e1b67c9 Mon Sep 17 00:00:00 2001
From: Michael Paquier <michael@paquier.xyz>
Date: Fri, 1 Feb 2019 10:35:46 +0900
Subject: [PATCH] Fix use of dangling pointer in heap_delete() when logging
 replica identity

When logging the replica identity of a deleted tuple, XLOG_HEAP_DELETE
records include references of the old tuple.  Its data is stored in an
intermediate variable used to register this information for the WAL
record, but this variable gets away from the stack when the record gets
actually inserted.

Spotted by clang's AddressSanitizer.

Author: Stas Kelvish
Discussion: https://postgr.es/m/085C8825-AD86-4E93-AF80-E26CDF03D1EA@postgrespro.ru
Backpatch-through: 9.4
---
 src/backend/access/heap/heapam.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c
index c7dd2be6fc1..0a9aafb7b62 100644
--- a/src/backend/access/heap/heapam.c
+++ b/src/backend/access/heap/heapam.c
@@ -3290,6 +3290,7 @@ l1:
 	if (RelationNeedsWAL(relation))
 	{
 		xl_heap_delete xlrec;
+		xl_heap_header xlhdr;
 		XLogRecPtr	recptr;
 
 		/* For logical decode we need combocids to properly decode the catalog */
@@ -3320,8 +3321,6 @@ l1:
 		 */
 		if (old_key_tuple != NULL)
 		{
-			xl_heap_header xlhdr;
-
 			xlhdr.t_infomask2 = old_key_tuple->t_data->t_infomask2;
 			xlhdr.t_infomask = old_key_tuple->t_data->t_infomask;
 			xlhdr.t_hoff = old_key_tuple->t_data->t_hoff;
-- 
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