ckermit uses the default /var/lock
folder which is "rwxr-xr-x 5 root root".
ckermit is patched to handle the environment variable LOCK_DIR to specifiy another lock directory.
Archlinux no longer provides the lock directory /var/lock/lockdev
to allow users in the lock group to read/write into it.
Archlinux should put back the folder /var/lock/lockdev
which would be: "drwxrwxr-x 2 root lock": it is unclear why they have removed it.