postgres.git / summary / log / commit / refs

commit    6d554e3fcd6fb8be2dbcbd3521e2947ed7a552cb
Author:   Tomas Vondra <tomas.vondra@postgresql.org>
Date:     Sun Jan 23 01:49:41 2022 +0000
First released in: 15.0, 13.6, 14.2

    Check syscache result in AlterStatistics
    
    The syscache lookup may return NULL even for valid OID, for example due
    to a concurrent DROP STATISTICS, so a HeapTupleIsValid is necessary.
    Without it, it may fail with a segfault.
    
    Reported by Alexander Lakhin, patch by me. Backpatch to 13, where ALTER
    STATISTICS ... SET STATISTICS was introduced.
    
    Backpatch-through: 13
    Discussion: https://postgr.es/m/17372-bf3b6e947e35ae77%40postgresql.org


 src/backend/commands/statscmds.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/backend/commands/statscmds.c b/src/backend/commands/statscmds.c
index f7419b8f562..54a190722df 100644
--- a/src/backend/commands/statscmds.c
+++ b/src/backend/commands/statscmds.c
@@ -657,6 +657,8 @@ AlterStatistics(AlterStatsStmt *stmt)
 	rel = table_open(StatisticExtRelationId, RowExclusiveLock);
 
 	oldtup = SearchSysCache1(STATEXTOID, ObjectIdGetDatum(stxoid));
+	if (!HeapTupleIsValid(oldtup))
+		elog(ERROR, "cache lookup failed for extended statistics object %u", stxoid);
 
 	/* Must be owner of the existing statistics object */
 	if (!pg_statistics_object_ownercheck(stxoid, GetUserId()))


[parent: 62e28097cebf]