Yeah, it's pretty rare to have a program that's correct regardless of the behavior (and defects) of the layers below it -- supporting multiple platforms of cour

Yeah, it's pretty rare to have a program that's correct regardless of the behavior (and defects) of the layers below it -- supporting multiple platforms of course involves performing your verification activities on all of them. As you hint at, guard probes without stack probes don't provide guaranteed segfaults -- sparse access to stack allocations can skip the guard and smash another stack (or whatever) easily enough. And stack probes for large sparse allocations firmly make stack allocations more expensive than heap allocations (since pages must be allocated for the whole allocation, even if it's unused), which is a pretty huge downside.