From 9702054c37aa80cb60a16b2d80a475e9b27b087a Mon Sep 17 00:00:00 2001 From: Soumyadeep Chakraborty Date: Wed, 7 Feb 2024 18:04:43 -0800 Subject: [PATCH v1 1/1] Use memory barrier in DisownLatch Failing to do so may cause another process undergoing startup to see our pid associated with the latch during OwnLatch's sanity check. --- src/backend/storage/ipc/latch.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/src/backend/storage/ipc/latch.c b/src/backend/storage/ipc/latch.c index d8a69990b3a..332c5e0b2cf 100644 --- a/src/backend/storage/ipc/latch.c +++ b/src/backend/storage/ipc/latch.c @@ -493,6 +493,12 @@ DisownLatch(Latch *latch) Assert(latch->owner_pid == MyProcPid); latch->owner_pid = 0; + + /* + * Ensure that another backend reusing this PGPROC during startup sees that + * owner_pid = 0 and doesn't blow up in OwnLatch(). + */ + pg_memory_barrier(); } /* -- 2.34.1