From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jiri Pirko <jiri@resnulli.us>
Subject: Re: [Patch net] net_sched: fix a missing rcu barrier in
 mini_qdisc_pair_swap()
Date: Fri, 22 Dec 2017 11:24:24 +0100
Message-ID: <20171222102424.GE11519@nanopsycho>
References: <20171221072624.6204-1-xiyou.wangcong@gmail.com>
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Cc: netdev@vger.kernel.org, Jiri Pirko <jiri@mellanox.com>,
        John Fastabend <john.fastabend@gmail.com>
To: Cong Wang <xiyou.wangcong@gmail.com>
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Thu, Dec 21, 2017 at 08:26:24AM CET, xiyou.wangcong@gmail.com wrote:
>The rcu_barrier_bh() in mini_qdisc_pair_swap() is to wait for
>flying RCU callback installed by a previous mini_qdisc_pair_swap(),
>however we miss it on the tp_head==NULL path, which leads to that
>the RCU callback still uses miniq_old->rcu after it is freed together
>with qdisc in qdisc_graft(). So just add it on that path too.
>
>Fixes: 46209401f8f6 ("net: core: introduce mini_Qdisc and eliminate usage of tp->q for clsact fastpath ")
>Reported-by: Jakub Kicinski <jakub.kicinski@netronome.com>
>Tested-by: Jakub Kicinski <jakub.kicinski@netronome.com>
>Cc: Jiri Pirko <jiri@mellanox.com>
>Cc: John Fastabend <john.fastabend@gmail.com>
>Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>

Acked-by: Jiri Pirko <jiri@mellanox.com>