commit 7f36f363574d52e3671859c6e0d83b8cbe752000
Author: George Ma <guoqing.mgq@alibaba-inc.com>
Date:   Wed Aug 5 20:35:09 2026 +0800

    [tmp] builder_error_case_kill

diff --git a/mysql-test/suite/innodb/t/builder_error_case_kill.test b/mysql-test/suite/innodb/t/builder_error_case_kill.test
new file mode 100644
index 00000000000..8caf0167b8c
--- /dev/null
+++ b/mysql-test/suite/innodb/t/builder_error_case_kill.test
@@ -0,0 +1,57 @@
+--source include/have_debug.inc
+--source include/have_debug_sync.inc
+
+# Interrupt a table rebuild after the clustered-index Btree_load has released
+# its page. The interrupted parallel reader must clean up every Builder.
+CREATE TABLE t1 (
+  id INT AUTO_INCREMENT PRIMARY KEY,
+  c1 INT,
+  KEY idx_1(c1)
+) ENGINE=InnoDB;
+
+--disable_query_log
+DELIMITER |;
+CREATE PROCEDURE populate_t1(IN BASE INT, IN SIZE INT)
+BEGIN
+  DECLARE i INT DEFAULT BASE;
+  WHILE (i + 10 <= SIZE) DO
+    INSERT INTO t1(c1) VALUES
+      (i), (i+1), (i+2), (i+3), (i+4),
+      (i+5), (i+6), (i+7), (i+8), (i+9);
+    SET i = i + 10;
+  END WHILE;
+END|
+DELIMITER ;|
+
+CALL populate_t1(0, 11000);
+DROP PROCEDURE populate_t1;
+--enable_query_log
+
+SELECT COUNT(*) FROM t1;
+
+connect (con1,localhost,root,,);
+connection con1;
+let $ID= `SELECT @id := CONNECTION_ID()`;
+SET DEBUG_SYNC=
+  'ddl_btree_load_released SIGNAL btree_load_released WAIT_FOR kill_ddl';
+--send ALTER TABLE t1 ADD COLUMN c2 INT DEFAULT 20, ALGORITHM=INPLACE;
+
+connection default;
+let $ignore= `SELECT @id := $ID`;
+SET DEBUG_SYNC='now WAIT_FOR btree_load_released';
+KILL QUERY @id;
+SET DEBUG_SYNC='now SIGNAL kill_ddl';
+
+connection con1;
+--error ER_QUERY_INTERRUPTED
+--reap
+SET DEBUG_SYNC='RESET';
+
+connection default;
+disconnect con1;
+
+# A debug build detects a buffer-fixed page during DDL teardown.
+--source include/shutdown_mysqld.inc
+--source include/start_mysqld.inc
+
+DROP TABLE t1;
diff --git a/storage/innobase/btr/btr0load.cc b/storage/innobase/btr/btr0load.cc
index 9cdd01463a4..79afb081526 100644
--- a/storage/innobase/btr/btr0load.cc
+++ b/storage/innobase/btr/btr0load.cc
@@ -1009,6 +1009,7 @@ Btree_load::~Btree_load() noexcept {
 void Btree_load::release() noexcept {
   ut_ad(m_n_recs > 0);
   m_page_loaders[0]->release();
+  DEBUG_SYNC_C("ddl_btree_load_released");
 }
 
 void Btree_load::latch() noexcept {