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From: Nicolas Dichtel <nicolas.dichtel@6wind.com>
To: Cong Wang <xiyou.wangcong@gmail.com>, netdev@vger.kernel.org
Cc: sds@tycho.nsa.gov, e@eladraz.com, paul@paul-moore.com
Subject: Re: [Patch net] net: saving irq context for peernet2id()
Date: Thu, 20 Oct 2016 12:17:18 +0200	[thread overview]
Message-ID: <eced0989-d8bc-d34e-9ecb-8540d80a7173@6wind.com> (raw)
In-Reply-To: <1476946352-15770-1-git-send-email-xiyou.wangcong@gmail.com>

Le 20/10/2016 à 08:52, Cong Wang a écrit :
> A kernel warning inside __local_bh_enable_ip() was reported by people
> running SELinux, this is caused due to some SELinux functions
> (indirectly) call peernet2id() with IRQ disabled in process context,
> when we re-enable BH with IRQ disabled kernel complains. Shut up this
> warning by saving IRQ context in peernet2id(), BH is still implicitly
> disabled.

Franckly, reverting the original patch seems better for me. The intention for
that patch was "it's not needed", see the commit log:

"We never read or change netns id in hardirq context,
the only place we read netns id in softirq context
is in vxlan_xmit(). So, it should be enough to just
disable BH."

Now, we see that "it's needed" and that the analysis was wrong. If a race is
introduced by this patch, it will be hard to detect and fix it.


Regards,
Nicolas

  reply	other threads:[~2016-10-20 10:17 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-10-20  6:52 [Patch net] net: saving irq context for peernet2id() Cong Wang
2016-10-20 10:17 ` Nicolas Dichtel [this message]
2016-10-20 17:17   ` Cong Wang
2016-10-20 14:58 ` Stephen Smalley
2016-10-20 18:29   ` Cong Wang
2016-10-20 19:04     ` Cong Wang
2016-10-20 19:07     ` Paul Moore
2016-10-20 23:35       ` Cong Wang
2016-10-21  4:47         ` Cong Wang
2016-10-21 13:51           ` Stephen Smalley
2016-10-21 16:19         ` Paul Moore
2016-10-21 18:02           ` Cong Wang
2016-10-21 19:39             ` Richard Guy Briggs
2016-10-21 20:15               ` Paul Moore
2016-10-21 20:33                 ` David Miller
2016-10-21 20:53                   ` Paul Moore
2016-10-22  1:55                     ` Paul Moore
2016-10-22  3:34                       ` Cong Wang
2016-10-22  3:53                   ` Cong Wang
2016-10-21 20:03             ` Paul Moore
2016-10-22  3:26               ` Cong Wang
2016-10-22 19:02                 ` Paul Moore

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