After coming back to my desk I cannot unlock my screen. So again I have to go to my Mac or even Windows to google my shitty Linux problem. Nothing particular turns up. So I switch to another tty and rummage through the process list. Kill some java that took 11GB of RAM and Firefox that always keeps some zombies. Nothing.
Grep the processes: oh let's nuke "light-locker". Bingo.
The only downside of this brutal unlock: I cannot lock the screen again. So in any case another reboot? Wasn't this the standard repair method of that other OS that should not be named?