[elihu]

The Linux kernel makes a somewhat similar distinction between code that's executing in an atomic context and code that isn't. Atomic code can get stuck in an infinite loop or whatever, but what it isn't allowed to do is to go to sleep (i.e. put itself into a sleeping state and invoke the scheduler).

Atomic tasks are generally expected to do a finite amount of work that can be finished in a short time without waiting for anything else (except maybe a spinlock, which should be held by some other similarly-atomic task that will finish in a short time).