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From: Eric Dumazet <eric.dumazet@gmail.com>
To: Xin Long <lucien.xin@gmail.com>
Cc: network dev <netdev@vger.kernel.org>,
	davem@davemloft.net, hannes@stressinduktion.org
Subject: Re: [PATCH net] route: add rcu_read_lock when lookup route and update fnhe in __ip_do_redirect
Date: Mon, 01 Feb 2016 05:46:47 -0800	[thread overview]
Message-ID: <1454334407.7627.163.camel@edumazet-glaptop2.roam.corp.google.com> (raw)
In-Reply-To: <db60649416c596fc5e76930484b726cb180b14b8.1454322132.git.lucien.xin@gmail.com>

On Mon, 2016-02-01 at 18:22 +0800, Xin Long wrote:

> But there may be an issue in __ip_do_redirect():
>          } else {
>              if (fib_lookup(net, fl4, &res, 0) == 0) {
>                  struct fib_nh *nh = &FIB_RES_NH(res);
> 
>                  update_or_create_fnhe(nh, fl4->daddr, new_gw,
>                                0, 0);
>              }
> 
> Which is not running in rcu_read_lock(), it may update a fnhe that
> has been freed.
> 
> So fix it by adding rcu_read_lock() just like other parts.

But the whole __ip_do_redirect() needs to be called from rcu_read_lock()
already.

No need to add another rcu_read_lock() around fib_lookup()

How did you come doing this patch ? Any particular stack dump or
something ?

  reply	other threads:[~2016-02-01 13:46 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 [this message]
2016-02-01 17:16   ` Xin Long
2016-02-01 17:49     ` Eric Dumazet
2016-02-01 18:14       ` Xin Long

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