BTW I'm mostly sure as we specified in a previous email, this problem is not related to the security DSA, but with a race condition in an upgrade path handled by apt. (probably always here, but with systemd it might be occurring more frequently).
(it might have happened with a one-line patch, or even with a no change rebuild) A solution might be to do a "systemctl stop virtualbox" and check that no "VBoxSVC" is running. (and sorry for the bad experience you had) cheers, Gianfranco
