From mboxrd@z Thu Jan  1 00:00:00 1970
From: Cong Wang <cwang@twopensource.com>
Subject: Re: size overflow in function qdisc_tree_decrease_qlen net/sched/sch_api.c
Date: Tue, 1 Dec 2015 14:47:24 -0800
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Cc: pageexec@freemail.hu, Daniele Fucini <dfucini@gmail.com>,
	netdev <netdev@vger.kernel.org>,
	Jamal Hadi Salim <jhs@mojatatu.com>,
	David Miller <davem@davemloft.net>, spender@grsecurity.net,
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To: Eric Dumazet <eric.dumazet@gmail.com>
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On Tue, Dec 1, 2015 at 2:33 PM, Eric Dumazet <eric.dumazet@gmail.com> wrote:
> Hmm... it looks like we have a much more serious bug :
>
> qdisc_lookup() calls qdisc_match_from_root(dev->qdisc, handle) without
> proper lock being held, so we might actually crash the host,
> if qdisc_tree_decrease_qlen() happens at the time qdiscs are changed.
>
> qdisc_tree_decrease_qlen() needs serious care :(

Convert qdisc list to RCU protected?