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Date: Thu, 14 Nov 2013 12:55:51 +0100
From: Oleg Nesterov <oleg@redhat.com>
To: Tejun Heo <tj@kernel.org>
Cc: zhang.yi20@zte.com.cn, linux-kernel@vger.kernel.org,
        Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Subject: [PATCH 0/1]: (Was: kmod: avoid propagating PF_NO_SETAFFINITY into
	userspace child)
Message-ID: <20131114115551.GA30824@redhat.com>
References: <OFC3933D9B.5510E97E-ON48257C23.0007B7CD-48257C23.000A4246@zte.com.cn> <20131114052326.GA29031@mtj.dyndns.org> <20131114114039.GA29277@redhat.com>
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On 11/14, Oleg Nesterov wrote:
>
> Yes, but kernel_thread() is called by the worker thread which has
> PF_NO_SETAFFINITY, this flag is copied to child->flags.

Hmm, and it seems that create_worker() needs a minor fix, please see
the patch.

> Looks like Zhang is right... But I'd suggest to change flush_old_exec()
> instead (see "current->flags &= ...").

Yes.


But... May be we should (also?) change copy_flags() to clear
PF_NO_SETAFFINITY? Probably not, this can lead to the subtle behaviour
changes. But I am wondering if there is any kthread() which relies on
PF_NO_SETAFFINITY copied by kernel_thread().

Oleg.