His use case should be solvable with a timer and a kill. Then asking for a timeout version for the syscall is for convenience. But that's a bad guiding principl

His use case should be solvable with a timer and a kill. Then asking for a timeout version for the syscall is for convenience. But that's a bad guiding principle for system interface design. You want to keep things simple and orthogonal and that rules out a timeout parameter. Maybe a general way to cancel in-progress syscalls would do it? Anyway, as my late systems professor used to say: timeouts are always too short or too long.