Running connections hang forever when all tables are flushed and locked for a few seconds

For the backup of MariaDB we use VSShadow and therefore the following commands are executed:

DROP TABLE IF EXISTS ibbackup_binlog_marker;
CREATE TABLE ibbackup_binlog_marker(a INT) ENGINE=INNODB;
SET AUTOCOMMIT=0;
INSERT INTO ibbackup_binlog_marker VALUES (1);
USE mysql;
FLUSH TABLES WITH READ LOCK;
COMMIT;

With MariaDB 5.5 we didn't have any problems. But with MariaDB 10.1 all running connections hang forever and didn't return anymore when the commands above are executed. I have attachted the response of "show full processlist" and the minidump of MariaDB and the my.ini.