From ed6329cfa975a13c58c44676464585cda5d317b3 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Sun, 20 Dec 2020 12:38:32 -0500 Subject: [PATCH] Avoid memcpy() with same source and destination in pgstat_recv_replslot. Same type of issue as in commit 53d4f5fef and earlier fixes; also found by apparently-more-picky-than-the-buildfarm valgrind testing. This one is an oversight in commit 986816750. Since that's new in HEAD, no need for a back-patch. --- src/backend/postmaster/pgstat.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/src/backend/postmaster/pgstat.c b/src/backend/postmaster/pgstat.c index 6b60f293e9..d87d9d06ee 100644 --- a/src/backend/postmaster/pgstat.c +++ b/src/backend/postmaster/pgstat.c @@ -6916,15 +6916,15 @@ pgstat_recv_replslot(PgStat_MsgReplSlot *msg, int len) return; /* it must be a valid replication slot index */ - Assert(idx >= 0 && idx < max_replication_slots); + Assert(idx < nReplSlotStats); if (msg->m_drop) { /* Remove the replication slot statistics with the given name */ - memcpy(&replSlotStats[idx], &replSlotStats[nReplSlotStats - 1], - sizeof(PgStat_ReplSlotStats)); + if (idx < nReplSlotStats - 1) + memcpy(&replSlotStats[idx], &replSlotStats[nReplSlotStats - 1], + sizeof(PgStat_ReplSlotStats)); nReplSlotStats--; - Assert(nReplSlotStats >= 0); } else {