Comment # 2 on bug 1231199 from Franck Bui

(In reply to Alberto Planas Dominguez from comment #0)
> Attached the logs with systemd.log_level=debug and udev_log_devel=debug.
> After some debug with Fabian we found that systemd-cryptsetup is
> communicating with /run/udev/control (systemd-udevd-control.socket) but when
> systemd-udevd service is already down. This seems to be the cause of the
> block.

systemd-udevd.service is not supposed to be stopped during the shutdown
process, udevd is normally killed at the very last step before switching back
to initrd.

So I suspect that the unit is stopped in your case probably due to the
modifications you did during your debug session.

Can you provide the debug logs without any modifications of your own ?

Please still provide the strace of `systemd-cryptsetup detach` with the stack
traces (strace -k ...).