On Mon, 30 Jun 2025 19:10:09 -0700 Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote: > On Mon, 30 Jun 2025 at 17:54, Steven Rostedt <rostedt@xxxxxxxxxxx> wrote: > > > > + /* stack going in wrong direction? */ > > + if (cfa <= state->sp) > > + goto done; > > I suspect this should do a lot more testing. Sure. > > > + /* Find the Return Address (RA) */ > > + if (get_user(ra, (unsigned long *)(cfa + frame->ra_off))) > > + goto done; > > + > > + if (frame->fp_off && get_user(fp, (unsigned long __user *)(cfa + frame->fp_off))) > > + goto done; > > .. and this should check the frame for validity too. At a minimum it > should be properly aligned, but things like "it had better be above > the current frame" to avoid having some loop would seem to be a good > idea. Makes sense. > > Maybe even check that it's the same vma? Hmm, I call on to Jens Remus and ask if s390 can do anything whacky here? Where something that isn't allowed on other architectures may be allowed there? I know s390 has some strange type of stack usage. -- Steve
