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From: Paul Menage <paul@paulmenage.org>
Date: Wed, 19 Oct 2011 01:00:22 -0700
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Subject: Re: [patch-final] Re: patch] cpusets, cgroups: disallow attaching kthreadd
To: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>, LKML <linux-kernel@vger.kernel.org>,
        Tejun Heo <htejun@gmail.com>, Li Zefan <lizf@cn.fujitsu.com>,
        David Rientjes <rientjes@google.com>
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On Wed, Oct 19, 2011 at 12:54 AM, Peter Zijlstra <a.p.zijlstra@chello.nl> wrote:
> I really think that if we want to restrain userspace from doing
> something stupid we might as well do something that makes sense,

Totally agreed. There are two solutions proposed, both of which make
sense as a method of solving the problem, and which have different
levels of effect on the existing user-visible API. So which do we
prefer?

If you just want to make sure people think about it before there's a
problem rather than after, then an alternative would be to have a flag
in cgroup_subsys such as allow_kthreadd, which defaults to false and
can be explicitly set to true for subsystems that are kthreadd-safe.

Paul