Author: George Ma <guoqing.mgq@alibaba-inc.com>
Date:   Wed Sep 2 20:00:45 2026 +0800

    bug #121211 test case

diff --git a/mysql-test/suite/innodb/t/rtree_rebuild_sync_lob_repro-master.opt b/mysql-test/suite/innodb/t/rtree_rebuild_sync_lob_repro-master.opt
new file mode 100644
index 00000000000..67c8423cf2a
--- /dev/null
+++ b/mysql-test/suite/innodb/t/rtree_rebuild_sync_lob_repro-master.opt
@@ -0,0 +1 @@
+--innodb_buffer_pool_size=5M
diff --git a/mysql-test/suite/innodb/t/rtree_rebuild_sync_lob_repro.test b/mysql-test/suite/innodb/t/rtree_rebuild_sync_lob_repro.test
new file mode 100644
index 00000000000..36c5c51db49
--- /dev/null
+++ b/mysql-test/suite/innodb/t/rtree_rebuild_sync_lob_repro.test
@@ -0,0 +1,40 @@
+--source include/have_debug.inc
+--source include/have_debug_sync.inc
+
+CREATE TABLE t1 (
+  id INT NOT NULL AUTO_INCREMENT,
+  c LONGBLOB,
+  pad CHAR(60) NOT NULL,
+  g LINESTRING NOT NULL,
+  PRIMARY KEY (id),
+  SPATIAL KEY sp_g (g)
+) ENGINE=InnoDB ROW_FORMAT=DYNAMIC;
+
+INSERT INTO t1 (c, pad, g)
+VALUES
+  (REPEAT('x', 6 * 1024 * 1024), REPEAT('a', 60),
+   ST_GeomFromText('LINESTRING(0 0, 1 1, 2 2)')),
+  (REPEAT('x', 6 * 1024 * 1024), REPEAT('b', 60),
+   ST_GeomFromText('LINESTRING(0 0, 1 1, 2 2)')),
+  (REPEAT('x', 6 * 1024 * 1024), REPEAT('c', 60),
+   ST_GeomFromText('LINESTRING(0 0, 1 1, 2 2)'));
+
+--connect (con1, localhost, root,,)
+# Force the clustered-index builder to flush after two spatial tuples are cached.
+SET DEBUG='+d,ddl_buf_add_two';
+# Stop only after savepoint() has released the source-page latch.
+SET DEBUG_SYNC='ddl_bulk_inserter_latches_released SIGNAL ddl_latches_released WAIT_FOR ddl_continue';
+--send ALTER TABLE t1 ENGINE=InnoDB, ALGORITHM=INPLACE
+
+--connection default
+SET DEBUG_SYNC='now WAIT_FOR ddl_latches_released';
+SET DEBUG_SYNC='now SIGNAL ddl_continue';
+
+--connection con1
+--reap
+CHECK TABLE t1;
+SET DEBUG='-d,ddl_buf_add_two';
+
+--connection default
+SET DEBUG_SYNC='RESET';
+DROP TABLE t1;