Re: [PATCH 08/17] ptrace/m68k: Stop open coding ptrace_report_syscall

On Mon, Jan 10, 2022 at 04:20:03PM +0000, Al Viro wrote:

Geert, do you see any problems with that?  The only difference is that
current->ptrace_message would be set to 1 for ptrace stop on entry and
2 - on leave.  Currently m68k just has it 0 all along.

It is user-visible (the whole point is to let the tracer see which
stop it is - entry or exit one), so somebody using PTRACE_GETEVENTMSG
on syscall stops would start seeing 1 or 2 instead of "0 all along".
That's how it works on all other architectures (including m68k-nommu),
and I doubt that anything in userland will get broken.

Behaviour of PTRACE_GETEVENTMSG for other stops (fork, etc.) remains
as-is, of course.

Actually, the current behaviour is "report what the last PTRACE_GETEVENTMSG
has reported, whatever kind of stop that used to be for".  So I very much
doubt that anything could break there.