diff --git a/src/test/regress/expected/create_am.out b/src/test/regress/expected/create_am.out
index 84da403afc..b9dc82dd3c 100644
--- a/src/test/regress/expected/create_am.out
+++ b/src/test/regress/expected/create_am.out
@@ -102,8 +102,13 @@ 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;
 --
 -- Test table access methods
 --
diff --git a/src/test/regress/sql/create_am.sql b/src/test/regress/sql/create_am.sql
index a7f6de7e9b..97df244d17 100644
--- a/src/test/regress/sql/create_am.sql
+++ b/src/test/regress/sql/create_am.sql
@@ -70,7 +70,12 @@ 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;
 
 
 --