Programs using mmap have to be prepared for SIGBUS on mapped region access anyway --- consider the surprise removal (yanking out USB stick) case. That few prog

Programs using mmap have to be prepared for SIGBUS on mapped region access anyway --- consider the surprise removal (yanking out USB stick) case. That few programs, especially native code ones, bother to make themselves robust against this failure mode of mmap doesn't make it any less part of the mmap contract between the kernel and userspace.