MariaDB server is running in 100% on one cpu

MariaDB server is running regularly in an endless loop in which one cpu is consuming 100%.
An output of "show full processlist" showed no progress anymore.

An analysis of the created minidump shows that the thread with id 3574 consumed most of the cpu.
0:000> !runaway
User Mode Time
Thread Time
15:3574 0 days 5:59:41.546
18:43a4 0 days 0:02:40.625
23:290c 0 days 0:01:22.109
...