From 113d3591b859fb8dc191bc0599d1ad62d91f1aa4 Mon Sep 17 00:00:00 2001 From: Fujii Masao Date: Wed, 4 Nov 2020 21:49:00 +0900 Subject: [PATCH] Fix segmentation fault that commit ac22929a26 caused. Commit ac22929a26 changed recoveryWakeupLatch so that it's reset to NULL at the end of recovery. This change could cause a segmentation fault in the buildfarm member 'elver'. Previously the latch was reset to NULL after calling ShutdownWalRcv(). But there could be a window between ShutdownWalRcv() and the actual exit of walreceiver. If walreceiver set the latch during that window, the segmentation fault could happen. To fix the issue, this commit changes walreceiver so that it sets the latch only when the latch has not been reset to NULL yet. Author: Fujii Masao Discussion: https://postgr.es/m/5c1f8a85-747c-7bf9-241e-dd467d8a3586@iki.fi --- src/backend/access/transam/xlog.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index e081bf9260..a1078a7cfc 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -12673,7 +12673,8 @@ CheckPromoteSignal(void) void WakeupRecovery(void) { - SetLatch(XLogCtl->recoveryWakeupLatch); + if (XLogCtl->recoveryWakeupLatch) + SetLatch(XLogCtl->recoveryWakeupLatch); } /*