LP:906323 - Query "stop slave" hangs

On various of our slave servers, we had problems with replication. It appears this started with hardware issues on our central MariaDB master (power failures). Trying to stop replication with "mysql -e 'stop slave'" resulted in the query simply getting stuck. MySQL wouldn't respond anymore to any queries relating to replication (e.g. show slave status). The only way to fix this, appeared to be to remove the /var/lib/mysql/master.info file and manually setting the correct replication values again after startup. I've made a full copy of a database in such a problematic state (both /var/log/mysql and /var/lib/mysql), uploaded that to FTP. Running MariaDB 5.2.9