Просто остановите и перезапустите MySQL в обычном режиме.

Редактировать

В противном случае:

Убедитесь, что вы сбросили привилегии:

GRANT ALL PRIVILEGES ON *.* TO 'root'@'%' WITH GRANT OPTION;
FLUSH PRIVILEGES;

Из документации :

FLUSH PRIVILEGES

Reloads the privileges from the grant tables in the mysql database.

The server caches information in memory as a result of GRANT and CREATE USER statements. This memory is not released by the corresponding REVOKE and DROP USER statements, so for a server that executes many instances of the statements that cause caching, there will be an increase in memory use. This cached memory can be freed with FLUSH PRIVILEGES.