diff --git a/src/test/regress/expected/create_am.out b/src/test/regress/expected/create_am.out
index 47dd885c4e9..0b8ba6dbfab 100644
--- a/src/test/regress/expected/create_am.out
+++ b/src/test/regress/expected/create_am.out
@@ -97,5 +97,10 @@ ERROR:  cannot drop access method gist2 because other objects depend on it
 DETAIL:  index grect2ind2 depends on operator class box_ops for access method gist2
 HINT:  Use DROP ... CASCADE to drop the dependent objects too.
 -- Drop access method cascade
+-- To prevent a (rare) deadlock against autovacuum,
+-- we must lock the table that owns the index that will be dropped
+BEGIN;
+LOCK TABLE fast_emp4000;
 DROP ACCESS METHOD gist2 CASCADE;
 NOTICE:  drop cascades to index grect2ind2
+COMMIT;
diff --git a/src/test/regress/sql/create_am.sql b/src/test/regress/sql/create_am.sql
index 3e0ac104f3c..1aa338d3e67 100644
--- a/src/test/regress/sql/create_am.sql
+++ b/src/test/regress/sql/create_am.sql
@@ -65,4 +65,9 @@ ROLLBACK;
 DROP ACCESS METHOD gist2;
 
 -- Drop access method cascade
+-- To prevent a (rare) deadlock against autovacuum,
+-- we must lock the table that owns the index that will be dropped
+BEGIN;
+LOCK TABLE fast_emp4000;
 DROP ACCESS METHOD gist2 CASCADE;
+COMMIT;