Here are two oopslogs and the telepathy-ring core dump (can someone please forward it?) which (supposedly) led to them. I was on the street and was gonna receive sms and a phone call. Looks like they came simultaneously, maybe that's the problem. Or maybe it just turned off because it was cold, -10°C at most. But it booted afterwards.

Edit: attaching mtd2 on freemangordon's request.

kernel-config: http://pastebin.com/q8ye84aa

Edit 2: Bug tracker is readonly.