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Date: Wed, 14 Mar 2012 19:55:10 +0100
From: Oleg Nesterov <oleg@redhat.com>
To: Andrew Morton <akpm@linux-foundation.org>,
        Linus Torvalds <torvalds@linux-foundation.org>
Cc: Djalal Harouni <tixxdz@opendz.org>, Alan Cox <alan@lxorguk.ukuu.org.uk>,
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Subject: [PATCH 0/1] (Was: self_exec_id/parent_exec_id && CLONE_PARENT)
Message-ID: <20120314185510.GA14172@redhat.com>
References: <1331421919-15499-1-git-send-email-tixxdz@opendz.org> <1331421919-15499-2-git-send-email-tixxdz@opendz.org> <20120311172512.GA2729@redhat.com> <20120311174953.GB2729@redhat.com> <CA+55aFx43nZmhRg5Qv5x-4BdgcM-y80ECrgC8mCWc0RqU+_8rQ@mail.gmail.com>
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On 03/11, Linus Torvalds wrote:
>
> On Sun, Mar 11, 2012 at 10:49 AM, Oleg Nesterov <oleg@redhat.com> wrote:
> >
> > I am also asking because the change above looks like the fix to me.
> > The child must not control its ->exit_signal, it is the parent who
> > decides which signal the child should use for notification.
> >
> > And to me, clone(CLONE_PARENT | SIGXXX) looks like a violation of
> > rule above.
>
> SIGXXX is for doing things like AIO with threads, but it would never
> be used together with CLONE_PARENT, that would be odd and wrong.
>
> So I think we could disallow that - or at least try. See if anybody
> notices, and if it breaks anything.
>
> The rule about the Linux ABI is not that the ABI is set in stone. It's
> that we can't break any existing binaries. And *maybe* there are users
> of CLONE_PARENT and special signals, but it sounds unlikely and would
> probably confuse real programs. So feel free to just try it (early in
> the 3.4 merge window - not at this point, though).

OK, nobody seems to object.

Andrew, could you take this patch?

As for self_exec_id/parent_exec_id, this needs cleanups and fixes
in any case. But perhaps we can kill them after this change.

Oleg.