[$] Suppressing SIGBUS signals

The mmap()system call creates a mapping for a range of virtual addresses; ithas a long list of options controlling just how that mapping should work.Ming Lin is proposingthe addition of yet another option, called MAP_NOSIGBUS, whichchanges the kernel's response when a process accesses an unmapped address.What this option does is relatively easy to understand; why it is useful takes a bit more explanation.