diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index a7a2d0ece13..a9b278bdf77 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -7854,17 +7854,12 @@ static void
 ATPrepDropExpression(Relation rel, AlterTableCmd *cmd, bool recurse, bool recursing, LOCKMODE lockmode)
 {
 	/*
-	 * Reject ONLY if there are child tables.  We could implement this, but it
-	 * is a bit complicated.  GENERATED clauses must be attached to the column
-	 * definition and cannot be added later like DEFAULT, so if a child table
-	 * has a generation expression that the parent does not have, the child
-	 * column will necessarily be an attlocal column.  So to implement ONLY
-	 * here, we'd need extra code to update attislocal of the direct child
-	 * tables, somewhat similar to how DROP COLUMN does it, so that the
-	 * resulting state can be properly dumped and restored.
+	 * Reject ONLY if there are child tables -- but only, of course, at the
+	 * top of the tree, otherwise it'd be impossible to run this command with
+	 * trees deeper than two levels.  Caller already got lock.
 	 */
-	if (!recurse &&
-		find_inheritance_children(RelationGetRelid(rel), lockmode))
+	if (!recurse && !recursing &&
+		find_inheritance_children(RelationGetRelid(rel), NoLock))
 		ereport(ERROR,
 				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 				 errmsg("ALTER TABLE / DROP EXPRESSION must be applied to child tables too")));
diff --git a/src/test/regress/expected/generated.out b/src/test/regress/expected/generated.out
index 3abaf4e23d4..67c15c302fe 100644
--- a/src/test/regress/expected/generated.out
+++ b/src/test/regress/expected/generated.out
@@ -960,6 +960,56 @@ Inherits: gtest30
 
 ALTER TABLE gtest30_1 ALTER COLUMN b DROP EXPRESSION;  -- error
 ERROR:  cannot drop generation expression from inherited column
+BEGIN;
+CREATE TABLE gtest30_1_1 () INHERITS (gtest30_1);
+ALTER TABLE gtest30 ALTER COLUMN b DROP EXPRESSION;
+\d gtest30_1_1
+            Table "public.gtest30_1_1"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+ b      | integer |           |          | 
+Inherits: gtest30_1
+
+ROLLBACK;
+-- test drop expression with subpartitions
+CREATE TABLE gtest_root (a int, b int, c int GENERATED ALWAYS AS (a + b) STORED) PARTITION BY LIST (a);
+CREATE TABLE gtest_node PARTITION OF gtest_root FOR VALUES IN (1) PARTITION BY LIST (b);
+CREATE TABLE gtest_leaf PARTITION OF gtest_node FOR VALUES IN (1);
+ALTER TABLE gtest_node ALTER COLUMN c DROP EXPRESSION;  -- fails
+ERROR:  cannot drop generation expression from inherited column
+ALTER TABLE ONLY gtest_root ALTER COLUMN c DROP EXPRESSION;  -- fails
+ERROR:  ALTER TABLE / DROP EXPRESSION must be applied to child tables too
+ALTER TABLE gtest_root ALTER COLUMN c DROP EXPRESSION;
+\d gtest_(root|node|leaf)
+             Table "public.gtest_leaf"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+ b      | integer |           |          | 
+ c      | integer |           |          | 
+Partition of: gtest_node FOR VALUES IN (1)
+
+       Partitioned table "public.gtest_node"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+ b      | integer |           |          | 
+ c      | integer |           |          | 
+Partition of: gtest_root FOR VALUES IN (1)
+Partition key: LIST (b)
+Number of partitions: 1 (Use \d+ to list them.)
+
+       Partitioned table "public.gtest_root"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+ b      | integer |           |          | 
+ c      | integer |           |          | 
+Partition key: LIST (a)
+Number of partitions: 1 (Use \d+ to list them.)
+
+DROP TABLE gtest_root;
 -- triggers
 CREATE TABLE gtest26 (
     a int PRIMARY KEY,
diff --git a/src/test/regress/sql/generated.sql b/src/test/regress/sql/generated.sql
index f3c0033879a..bf56c18ea59 100644
--- a/src/test/regress/sql/generated.sql
+++ b/src/test/regress/sql/generated.sql
@@ -480,6 +480,21 @@ ALTER TABLE ONLY gtest30 ALTER COLUMN b DROP EXPRESSION;  -- error
 \d gtest30
 \d gtest30_1
 ALTER TABLE gtest30_1 ALTER COLUMN b DROP EXPRESSION;  -- error
+BEGIN;
+CREATE TABLE gtest30_1_1 () INHERITS (gtest30_1);
+ALTER TABLE gtest30 ALTER COLUMN b DROP EXPRESSION;
+\d gtest30_1_1
+ROLLBACK;
+
+-- test drop expression with subpartitions
+CREATE TABLE gtest_root (a int, b int, c int GENERATED ALWAYS AS (a + b) STORED) PARTITION BY LIST (a);
+CREATE TABLE gtest_node PARTITION OF gtest_root FOR VALUES IN (1) PARTITION BY LIST (b);
+CREATE TABLE gtest_leaf PARTITION OF gtest_node FOR VALUES IN (1);
+ALTER TABLE gtest_node ALTER COLUMN c DROP EXPRESSION;  -- fails
+ALTER TABLE ONLY gtest_root ALTER COLUMN c DROP EXPRESSION;  -- fails
+ALTER TABLE gtest_root ALTER COLUMN c DROP EXPRESSION;
+\d gtest_(root|node|leaf)
+DROP TABLE gtest_root;
 
 -- triggers
 CREATE TABLE gtest26 (