Thread hang in 'Waiting for table metadata lock' on CREATE TABLE

--let $SOCKET= `SELECT @@global.socket`

--source include/have_innodb.inc

INSTALL PLUGIN Spider SONAME 'ha_spider.so';

CREATE USER Spider@localhost IDENTIFIED BY 'PWD123';

eval CREATE SERVER srv FOREIGN DATA WRAPPER MYSQL OPTIONS (SOCKET "$SOCKET", DATABASE 'test', USER 'Spider', PASSWORD 'PWD123');

CREATE TABLE t (c INT) ENGINE=InnoDB;

CREATE TABLE t1 (a INT) ENGINE=Spider COMMENT='WRAPPER "mysql", srv "srv", TABLE "t"';

LOCK TABLES t1 WRITE;

--error 12622

ALTER TABLE t1 CHANGE a b INT,ADD PRIMARY KEY(b);

UNLOCK TABLES;  # Not necessary to reproduce, but increases severity

CREATE TABLE t (a INT) ENGINE=InnoDB;

DROP TABLE t, t1;  # Cleanup

...

10.11.0>ALTER TABLE t1 CHANGE a b INT,ADD PRIMARY KEY(b);

ERROR 12622 (HY000): Can't use this operation before executing 'unlock tables'

10.11.0>UNLOCK TABLES;

Query OK, 0 rows affected (0.000 sec)

10.11.0>CREATE TABLE t (a INT) ENGINE=InnoDB;  # Hangs

10.11.0-dbg>SHOW FULL PROCESSLIST;

+----+-------------+-----------+------+---------+------+----------------------------------------------------+--------------------------------------+----------+

| Id | User        | Host      | db   | Command | Time | State                                              | Info                                 | Progress |

+----+-------------+-----------+------+---------+------+----------------------------------------------------+--------------------------------------+----------+

|  4 | root        | localhost | test | Query   |  164 | Waiting for table metadata lock                    | CREATE TABLE t (a INT) ENGINE=InnoDB |    0.000 |

|  5 | system user |           | NULL | Daemon  | NULL | Spider table background statistics action handler  | NULL                                 |    0.000 |

|  7 | system user |           | NULL | Daemon  | NULL | Spider table background statistics action handler  | NULL                                 |    0.000 |

|  6 | system user |           | NULL | Daemon  | NULL | Spider table background statistics action handler  | NULL                                 |    0.000 |

|  8 | system user |           | NULL | Daemon  | NULL | Spider table background statistics action handler  | NULL                                 |    0.000 |

|  9 | system user |           | NULL | Daemon  | NULL | Spider table background statistics action handler  | NULL                                 |    0.000 |

| 10 | system user |           | NULL | Daemon  | NULL | Spider table background statistics action handler  | NULL                                 |    0.000 |

| 11 | system user |           | NULL | Daemon  | NULL | Spider table background statistics action handler  | NULL                                 |    0.000 |

| 12 | system user |           | NULL | Daemon  | NULL | Spider table background cardinality action handler | NULL                                 |    0.000 |

| 14 | system user |           | NULL | Daemon  | NULL | Spider table background cardinality action handler | NULL                                 |    0.000 |

| 13 | system user |           | NULL | Daemon  | NULL | Spider table background cardinality action handler | NULL                                 |    0.000 |

| 16 | system user |           | NULL | Sleep   |  164 | Reset for next command                             | NULL                                 |    0.000 |

| 15 | system user |           | NULL | Daemon  | NULL | Spider table background cardinality action handler | NULL                                 |    0.000 |

| 17 | system user |           | NULL | Daemon  | NULL | Spider table background cardinality action handler | NULL                                 |    0.000 |

| 19 | system user |           | NULL | Daemon  | NULL | Spider table background cardinality action handler | NULL                                 |    0.000 |

| 20 | system user |           | NULL | Daemon  | NULL | Spider table background statistics action handler  | NULL                                 |    0.000 |

| 18 | system user |           | NULL | Daemon  | NULL | Spider table background cardinality action handler | NULL                                 |    0.000 |

| 22 | system user |           | NULL | Daemon  | NULL | Spider table background cardinality action handler | NULL                                 |    0.000 |

| 23 | system user |           | NULL | Daemon  | NULL | Spider table background cardinality action handler | NULL                                 |    0.000 |

| 24 | system user |           | NULL | Daemon  | NULL | Spider table background cardinality action handler | NULL                                 |    0.000 |

| 21 | system user |           | NULL | Daemon  | NULL | Spider table background statistics action handler  | NULL                                 |    0.000 |

| 25 | Spider      | localhost | test | Sleep   |  164 |                                                    | NULL                                 |    0.000 |

| 26 | root        | localhost | test | Query   |    0 | starting                                           | SHOW FULL PROCESSLIST                |    0.000 |

+----+-------------+-----------+------+---------+------+----------------------------------------------------+--------------------------------------+----------+

23 rows in set (0.001 sec)