Hi Mr. Thumshirn, after some tests I think I have found an important hint: The mutex.c issue occur immediately when a virtual machine, which is connect via fcoe, is destroyed with force by qemu (virsh destroy <vm>). In case of a normal shutdown only a message in der traget system is written to the message file that the rport is blocked for a while, but you can reconnect by the startup/power on of the system. I hope this helps you. Best regards Holger