[PATCH 1/4] ptrace: temporary revert the recent ptrace/jobctl rework

[Oleg Nesterov]

On 06/21, Roland McGrath wrote:
>
> > OK, so here's my (hacky) idea:
> > (1) Forget ptrace-via-utrace.  Have utrace be a separate thing.  This
> > way the recent ptrace changes won't matter.

This is what V2 does.

> > (2) But, what about ptrace co-existing well with utrace?  Make them
> > mutually exclusive - a ptraced-process can't be utraced and a
> > utraced-process can't be ptraced.
>
> We had this situation before for a while.  It has the substantial downside
> that e.g. you cannot do any system-wide systemtap tracing without making
> all strace and gdb use impossible.

Yes, we can't make them mutually exclusive, this can't work. So V2 tries
to teach them play well together.

> > Assuming the above is a semi-reasonable idea, it might be a lot less
> > work than updating the ptrace-via-utrace code to handle the new ptrace
> > changes.
>
> That's for Oleg to say.  (Sorry, Oleg. ;-)

Oh, I am not sure what is simpler ;)

Oleg.