Re: [RFC] is_global_init() called on global init sub-thread

From: Serge E. Hallyn
Date: Thu Dec 31 2015 - 21:29:07 EST


On Fri, Jan 01, 2016 at 10:33:53AM +0900, Sergey Senozhatsky wrote:
> On (12/31/15 19:18), Serge E. Hallyn wrote:
> > On Fri, Jan 01, 2016 at 10:10:35AM +0900, Sergey Senozhatsky wrote:
> > > On (12/31/15 19:08), Serge E. Hallyn wrote:
> > > > > re-upping https://www.redhat.com/archives/linux-audit/2013-December/msg00086.html
> > > > >
> > > > > Oleg Nesterov wrote:
> > > > >
> > > > > :Because is_global_init() is only true for the main thread of /sbin/init.
> > > > > :
> > > > > :Just look at oom_unkillable_task(). It tries to not kill init. But, say,
> > > > > :select_bad_process() can happily find a sub-thread of is_global_init()
> > > > > :and still kill it.
> > > > >
> > > > > this is still the case, isn't it? at least in some -stable kernels.
> > > > > is there (or was there) any reason this change has never been committed?
> > > > > (I'm particularly interested in is_global_init()).
> > > >
> > > > ... seems like it makes sense. Can you remind us which init you're having
> > > > to deal with?
> > > >
> > >
> > > systemd
> > >
> > > -ss
> >
> > Well it makes sense to me. The question is whether we are protecting the
> > thing running as init, or the 'physical' thread with pid 1. I think it's
> > the former, so let's push on this. Please resend the patch with a proper
> > signed-off-by, and feel free to add
>
> thanks. a bit puzzled, would reported-by Oleg and suggested-by Richard
> be appropriate?

Sounds good.

> (no objections if Oleg or Richard will submit it).

> > Acked-by: Serge Hallyn <serge.hallyn@xxxxxxxxxxxxx>
>
> -ss
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