MDEV-5955 Server crashes in handler::ha_external_lock or assertion `m_lock_type == 2' fails in handler::ha_close on disconnect with a locked temporary table

first unlock locked tables, then close and remove temporary

3 files changed, 13 insertions, 2 deletions

diff --git a/mysql-test/r/locked_temporary-5955.result b/mysql-test/r/locked_temporary-5955.result
new file mode 100644
index 00000000000..8999bdd39c4
--- /dev/null
+++ b/mysql-test/r/locked_temporary-5955.result
@@ -0,0 +1,2 @@
+CREATE TEMPORARY TABLE tmp (i INT) ENGINE=InnoDB;
+LOCK TABLES tmp AS p WRITE;
diff --git a/mysql-test/t/locked_temporary-5955.test b/mysql-test/t/locked_temporary-5955.test
new file mode 100644
index 00000000000..1ade63f4913
--- /dev/null
+++ b/mysql-test/t/locked_temporary-5955.test
@@ -0,0 +1,10 @@
+#
+# MDEV-5955 Server crashes in handler::ha_external_lock or assertion `m_lock_type == 2' fails in handler::ha_close on disconnect with a locked temporary table
+#
+
+--source include/have_innodb.inc
+--connect (con1,localhost,root,,)
+CREATE TEMPORARY TABLE tmp (i INT) ENGINE=InnoDB;
+LOCK TABLES tmp AS p WRITE;
+--disconnect con1
+
diff --git a/sql/sql_class.cc b/sql/sql_class.cc
index 4b9701c4eb5..91705de7c9b 100644
--- a/sql/sql_class.cc
+++ b/sql/sql_class.cc
@@ -1391,6 +1391,7 @@ void THD::cleanup(void)
 #endif
 
   mysql_ha_cleanup(this);
+  locked_tables_list.unlock_locked_tables(this);
 
   close_temporary_tables(this);
 
@@ -1398,8 +1399,6 @@ void THD::cleanup(void)
   trans_rollback(this);
   xid_cache_delete(&transaction.xid_state);
 
-  locked_tables_list.unlock_locked_tables(this);
-
   DBUG_ASSERT(open_tables == NULL);
   /*
     If the thread was in the middle of an ongoing transaction (rolled