rebooting node, unmounting configfs takes forever...

it's still there... what can be the cause, how to solve?

cman status:

# service cman status
Found stale lock file

what that means?

[update]
meanwhile I rebooted with

echo 1 > /proc/sys/kernel/sysrq
echo b > /proc/sysrq-trigger

but would like to understand what happens and how to manage...

Thanks, Marco