On Mon, Jun 21, 2021 at 04:14:36PM -0700, Linus Torvalds wrote:

On Mon, Jun 21, 2021 at 12:45 PM Al Viro [off-list ref] wrote:

quoted

quoted

Looks like sys_exit() and do_group_exit() would be the two places to
do it (do_group_exit() would handle the signal case and
sys_group_exit()).

Maybe...  I'm digging through that pile right now, will follow up when
I get a reasonably complete picture

We might have another possible way to solve this:

 (a) make it the rule that everybody always saves the full (integer)
register set in pt_regs

 (b) make m68k just always create that switch-stack for all system
calls (it's really not that big, I think it's like six words or
something)

 (c) admit that alpha is broken, but nobody really cares

	How would it help e.g. oopsen on the way out of timer interrupts?
IMO we simply shouldn't allow ptrace access if the tracee is in that kind
of state, on any architecture...