On Mon, Aug 22, 2016 at 03:11:32PM -0700, Linus Torvalds wrote: > On Thu, Aug 18, 2016 at 6:06 AM, Josh Poimboeuf <jpoim...@redhat.com> wrote: > > Convert arch_within_stack_frames() to use the new unwinder. > > Please don't do this. > > There's no real reason to unwind the stack frame. If it's not on the > current stack page, it shouldn't be a valid source anyway, so > unwidning things just seems entirely pointless. > > Quite frankly, I think the whole "look at the stack frames" logic > should be removed from this. It's classic crap that external patches > do. How many call-sites does it actually check, and how many of them > aren't already checked by the existing static checks for constant > addresses within existing objects?
I noticed the __compiletime_object_size() check is completely disabled for gcc >= 4.6, thanks to: 2fb0815c9ee6 ("gcc4: disable __compiletime_object_size for GCC 4.6+") AFAICT, that change went too far: it disabled both the compile-time *and* the runtime checks, so copy_from_user_overflow() is never called. Working on a couple of patches to try to fix that. -- Josh