This is indeed how certain language runtimes generate null pointer exceptions. It would be too slow to add comparisons against null to every use of a pointer. S

This is indeed how certain language runtimes generate null pointer exceptions. It would be too slow to add comparisons against null to every use of a pointer. So they handle SIGSEGV and raise the exception if the faulting access is on the null page. Interesting side question: if you have a struct bigger than a page, and you dereference the end of it... How big does it have to be to not get this behavior?