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

From: Al Viro
Date: Mon Jan 10 2022 - 11:25:25 EST


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.