In most systems it is all right [...] even to deadlock the entire system, as long as this event is detected automatically and doesn’t happen too often. The usual recovery is by crashing some processes, or even the entire system. At first this sounds terrible, but one crash a week is usually a cheap price to pay for 20% better performance. Of course the system must have decent error recovery, but that is required in any case, since there are so many other possible causes of a crash.