From b3d2f9ba716d4e53f628367838192ae0aa93a382 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Eren=20Ba=C5=9Fak?= <aamederen@gmail.com>
Date: Fri, 11 Aug 2017 15:43:52 +0300
Subject: [PATCH] Fix pg_worker_list use-after-free bug

This change fixes a use-after-free bug while renaming obsolete
`pg_worker_list.conf` file, which causes Citus to crash during upgrade
(or even extension creation) if `pg_worker_list.conf` exists.
---
 src/backend/distributed/utils/node_metadata.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/backend/distributed/utils/node_metadata.c b/src/backend/distributed/utils/node_metadata.c
index 0d68b96dc..cf7190d46 100644
--- a/src/backend/distributed/utils/node_metadata.c
+++ b/src/backend/distributed/utils/node_metadata.c
@@ -1367,14 +1367,14 @@ ParseWorkerNodeFileAndRename()
 		workerNodeList = lappend(workerNodeList, workerNode);
 	}
 
-	FreeFile(workerFileStream);
-	free(workerFilePath);
-
 	/* rename the file, marking that it is not used anymore */
 	appendStringInfo(renamedWorkerFilePath, "%s", workerFilePath);
 	appendStringInfo(renamedWorkerFilePath, ".obsolete");
 	rename(workerFilePath, renamedWorkerFilePath->data);
 
+	FreeFile(workerFileStream);
+	free(workerFilePath);
+
 	return workerNodeList;
 }