Re: [PATCH 0/2] fix the long standing exec vs kill race

From: Oleg Nesterov
Date: Mon Dec 03 2007 - 12:41:08 EST


On 12/03, Linus Torvalds wrote:
>
> On Sun, 2 Dec 2007, Oleg Nesterov wrote:
> >
> > Depends on
> > [PATCH] __group_complete_signal: fix coredump with group stop race
> > http://marc.info/?l=linux-kernel&m=119653436116036
> >
> > Needs review and testing.
> >
> > Please comment, I think at least the idea is promising.
>
> It looks clean and sane to me, but I'm currently more worried about
> 2.6.24, and even the first patch this depends on (coredump/stop race)
> makes me a bit nervous since all these things tend to have some rather
> subtle interactions with other parts that depended on the exact semantics
> of all the signal issues.
>
> So my gut feel - considering that none of the problems involved here are
> exactly new - is that this is good material for early in the 2.6.25 cycle.
>
> But I think the whole series looks ok, and if people press me and convince
> me it's (a) well tested and (b) needed early, then I guess it can be
> pushed into 2.6.24.

No, no, I don't think this should be pushed into 2.6.24 (even the first patch).

These problems are very old afaics, and nobody complained so far.

Even if correct, this needs more testing. I don't think this can break exec
or coredump in some "obvious" way, but I'm afraid this can introduce new
races / corner cases.

<offtopic>

I hope that with the new meaning of ->group_exit_task we can re-introduce the
"coredump signal "freezes" the thread group at sender's side" property, but we
need some hack to do this. OTOH, it was always a hack.

</offtopic>

Oleg.

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