SHOW SPATIAL_REF_SYS and SHOW SYSTEM_VARIABLES return empty results with numerous warnings

MariaDB [test]> SHOW SYSTEM_VARIABLES;

Query OK, 0 rows affected, 18515 warnings (0.02 sec)

MariaDB [(none)]> show warnings;

ERROR 2006 (HY000): MySQL server has gone away

No connection. Trying to reconnect...

Connection id:    6

Current database: *** NONE ***

Empty set (0.00 sec)

MariaDB [(none)]> select @@max_allowed_packet;

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

| @@max_allowed_packet |

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

|           1073741824 |

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

1 row in set (0.00 sec)