SELECT SLEEP(1) Hangs indefinitely with Time 0

INSERT INTO t VALUES (1);

CREATE TABLE parent (a INT KEY,b INT);

CREATE TABLE t (a INT KEY,FOREIGN KEY(a) REFERENCES parent (a) ON DELETE CASCADE) COLLATE=BIG5_nopad_bin;

SET GLOBAL innodb_status_output=1;

SELECT SLEEP (1);

MariaDB [(none)]> show processlist;

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

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

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

|  7 | root | localhost | test | Query   |    0 | User sleep | SELECT SLEEP (1) |    0.000 |

|  8 | root | localhost | NULL | Query   |    0 | starting   | show processlist |    0.000 |

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

2 rows in set (0.000 sec)