On Fri, Aug 19, 2016 at 11:27:18AM -0700, Kees Cook wrote: > On Thu, Aug 18, 2016 at 6:06 AM, Josh Poimboeuf <[email protected]> wrote: > > Convert arch_within_stack_frames() to use the new unwinder. > > > > This also changes some existing behavior: > > > > - Skip checking of pt_regs frames. > > - Warn if it can't reach the grandparent's stack frame. > > - Warn if it doesn't unwind to the end of the stack. > > > > Signed-off-by: Josh Poimboeuf <[email protected]> > > All the stuff touching usercopy looks good to me. One question, > though, in looking through the unwinder. It seems like it's much more > complex than just the frame-hopping that the old > arch_within_stack_frames() did, but I'm curious to hear what you think > about its performance. We'll be calling this with every usercopy that > touches the stack, so I'd like to be able to estimate the performance > impact of this replacement...
Yeah, good point. I'll take some measurements from before and after and get back to you. -- Josh
