On Mon, 30 Jun 2025 19:10:09 -0700
Linus Torvalds [off-list ref] wrote:
On Mon, 30 Jun 2025 at 17:54, Steven Rostedt [off-list ref] wrote:
quoted
+ /* stack going in wrong direction? */
+ if (cfa <= state->sp)
+ goto done;
I suspect this should do a lot more testing.
Sure.
quoted
+ /* 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