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From: Xin Long <lucien.xin@gmail.com>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: network dev <netdev@vger.kernel.org>, davem <davem@davemloft.net>,
	Hannes Frederic Sowa <hannes@stressinduktion.org>
Subject: Re: [PATCH net] route: add rcu_read_lock when lookup route and update fnhe in __ip_do_redirect
Date: Tue, 2 Feb 2016 02:14:50 +0800	[thread overview]
Message-ID: <CADvbK_eQEv+SVucvZcDrdf6y6xHt1Zuu0Fs69KvvHoHL-cw-aQ@mail.gmail.com> (raw)
In-Reply-To: <1454348968.7627.174.camel@edumazet-glaptop2.roam.corp.google.com>

On Tue, Feb 2, 2016 at 1:49 AM, Eric Dumazet <eric.dumazet@gmail.com> wrote:
> On Tue, 2016-02-02 at 01:16 +0800, Xin Long wrote:
>
>> no, no stack dump was found.
>> by reviewing code, I found it when I cooked another patch.
>>
>> and the path that __ip_do_redirect() is called should be:
>>
>> icmp_rcv |-> icmp_unreach  -\
>>               |-> icmp_redirect -> icmp_socket_deliver -> ipprot->err_handler()
>> [tcp_v4/6_err, sctp_v4/6_err, dccp_v4/6_err, udpv4/6_err ...]
>>
>> -> ... -> __ip_do_redirect()
>>
>> I checked the codes for many times, didn't find any rcu_lock on this path,
>> unless we treat BH as rcu_lock.
>
> Well I believe you missed something yes.
>
> All RX paths run in rcu_read_lock()
>
> ip_local_deliver_finish()
> ipv6_rcv()
> ip6_input_finish()

Ah, right, I never thought the lock might start from ip_rcv.
Thanks, Eric.

>
>
>

      reply	other threads:[~2016-02-01 18:14 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-02-01 10:22 [PATCH net] route: add rcu_read_lock when lookup route and update fnhe in __ip_do_redirect Xin Long
2016-02-01 13:46 ` Eric Dumazet
2016-02-01 17:16   ` Xin Long
2016-02-01 17:49     ` Eric Dumazet
2016-02-01 18:14       ` Xin Long [this message]

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