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From: Jamal Hadi Salim <jhs@mojatatu.com>
To: Cong Wang <xiyou.wangcong@gmail.com>, netdev@vger.kernel.org
Cc: John Fastabend <john.fastabend@gmail.com>,
	Cong Wang <cwang@twopensource.com>
Subject: Re: [Patch net] act_mirred: fix a race condition on mirred_list
Date: Mon, 5 Oct 2015 07:58:36 -0400	[thread overview]
Message-ID: <561265EC.6050906@mojatatu.com> (raw)
In-Reply-To: <1443724663-27158-1-git-send-email-xiyou.wangcong@gmail.com>

Hi Cong,

I am wondering if making the bindcount or refcount atomic would help?
How does this bug get created? i.e the RTNL is still around.
Why is this specific to mirred only?

cheers,
jamal


On 10/01/15 14:37, Cong Wang wrote:
> After commit 1ce87720d456 ("net: sched: make cls_u32 lockless")
> we began to release tc actions in a RCU callback. However,
> mirred action relies on RTNL lock to protect the global
> mirred_list, therefore we could have a race condition
> between RCU callback and netdevice event, which caused
> a list corruption as reported by Vinson.
>
> Instead of relying on RTNL lock, introduce a spinlock to
> protect this list.
>
> Note, in non-bind case, it is still called with RTNL lock,
> therefore should disable BH too.
>

  parent reply	other threads:[~2015-10-05 11:58 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-10-01 18:37 [Patch net] act_mirred: fix a race condition on mirred_list Cong Wang
2015-10-01 18:37 ` [Patch net] act_mirred: always release tcf hash Cong Wang
2015-10-05 12:14   ` Jamal Hadi Salim
2015-10-05 13:31   ` David Miller
2015-10-05 11:58 ` Jamal Hadi Salim [this message]
2015-10-05 12:07   ` [Patch net] act_mirred: fix a race condition on mirred_list Jamal Hadi Salim
2015-10-05 13:31 ` David Miller

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