Additional uncaught exception thrown while handling exception.

Original

PDOException: SQLSTATE[HY000] [2002] Connection refused in lock_may_be_available() (line 167 of /var/www/html/includes/lock.inc).

Additional

PDOException: SQLSTATE[HY000] [2002] Connection refused in system_list() (line 165 of /var/www/html/includes/module.inc).