Well at least in this case the timing won't be arbitrary. Execution will have blocked waiting on the read and you will (AFAIK) receive the signal promptly in this case. Since the code in question was doing IO that you knew could fail handling the situation can be as simple as setting a flag from within the signal handler.

I'm unclear what would happen in the event you had configured the mask to force SIGBUS to a different thread. Presumably undefined behavior.

> If multiple standard signals are pending for a process, the order in which the signals are delivered is unspecified.

That could create the mother of all edgecases if a different signal handler assumed the variable you just failed to read into was in a valid state. More fun footguns I guess.