Re: [PATCH 2/3] work_on_cpu: Use our own workqueue.

From: Pavel Machek
Date: Thu Feb 05 2009 - 07:20:11 EST


> On Wed, 4 Feb 2009 22:35:19 +0100
> Ingo Molnar <mingo@xxxxxxx> wrote:
>
> >
> > * Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote:
> >
> > > mm/pdflush.c:
> > >
> > > wtf what the heck is all that stuff and who added it? weird.
> > >
> > > Leave it alone I guess. Can admins manually move kernel threads to
> > > other CPUs?
> >
> > they can - and there's even tools that do that (there's some -rt tools where
> > you can put kernel thread priorities into a config file).
> >
>
> Oh well, DontDoThatThen.
>
> I expect that the same argument applies to most of the set_cpus_allowed()
> callsites - they're run by root-only code. Sure, root can (with
> careful timing) move root's own thread onto the wrong CPU in the middle
> of microcode loading. In which case root gets to own both pieces.

Actually... with selinux and similar extensions, being root should not
mean you can run arbitrary code at the kernel level....


--
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