Comment by stmw
8 years ago
Oh, I was imagining that referred to a situation where you have a stack (say 8K to keep it aligned), then a 4K guard page (which faults when you grow past it), and then someone probes past it, at 16K. Which may be mapped to all kinds of other things, no?
Sure, but the thing is something would've already probed into the 4K guard page before you had a chance to probe past it. If your stack guard page is the next thing up on the stack and you call that vDSO function, then sure, it'll probe past the guard page. But if all your code is built with -fstack-check then that guarantees you should have already crashed by having some prior function in the call stack probe into that guard page.