Re: [PATCH 1/1] signals: introduce send_sigkill() helper

From: KOSAKI Motohiro
Date: Wed Jun 16 2010 - 06:01:25 EST


> Andrew, please drop
>
> signals-introduce-send_sigkill-helper.patch
>
> I am stupid.
>
> On 06/10, Oleg Nesterov wrote:
> >
> > Cleanup, no functional changes.
> >
> > There are a lot of buggy SIGKILL users in kernel. For example, almost
> > every force_sig(SIGKILL) is wrong. force_sig() is not safe, it assumes
> > that the task has the valid ->sighand, and in general it should be used
> > only for synchronous signals. send_sig(SIGKILL, p, 1) or
> > send_xxx(SEND_SIG_FORCED/SEND_SIG_PRIV) is not right too but this is not
> > immediately obvious.
> >
> > The only way to correctly send SIGKILL is send_sig_info(SEND_SIG_NOINFO)
>
> No, SEND_SIG_NOINFO doesn't work too. Oh, can't understand what I was
> thinking about. current is the random task, but send_signal() checks
> if the caller is from-parent-ns.
>
> > Note: we need more cleanups here, this is only the first change.
>
> We need the cleanups first. Until then oom-killer has to use force_sig()
> if we want to kill the SIGNAL_UNKILLABLE tasks too.

This definitely needed. OOM-Killer is not racist ;)

Thanks.


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