linux-kernel - Re: [PATCH v2] openvswitch: supply a dummy err_handler of gre_cisco

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Date:	Tue, 8 Apr 2014 17:46:00 -0700
From:	Jesse Gross <jesse@...ira.com>
To:	wei zhang <asuka.com@....com>
Cc:	David Miller <davem@...emloft.net>,
	"dev@...nvswitch.org" <dev@...nvswitch.org>,
	netdev <netdev@...r.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2] openvswitch: supply a dummy err_handler of
 gre_cisco_protocol to prevent kernel crash

On Fri, Apr 4, 2014 at 9:20 PM, wei zhang <asuka.com@....com> wrote:
> At 2014-04-05 07:05:59,"Jesse Gross" <jesse@...ira.com> wrote:
>>On Tue, Apr 1, 2014 at 5:23 PM, Wei Zhang <asuka.com@....com> wrote:
>>>
>>> v2 -> v1: use the same logic of the gre_rcv() to distinguish which packet is
>>> intended to us!
>>
>>As a tip on kernel process: if you put the version information after
>>three dashes below the signed-off-by line then git will automatically
>>remove it when the final patch is applied.
>
> Thanks, should I modify it and send a v3 patch?
>
>>
>>> diff --git a/net/openvswitch/vport-gre.c b/net/openvswitch/vport-gre.c
>>> index a3d6951..f391df1 100644
>>> --- a/net/openvswitch/vport-gre.c
>>> +++ b/net/openvswitch/vport-gre.c
>>> @@ -110,6 +110,21 @@ static int gre_rcv(struct sk_buff *skb,
>>>         return PACKET_RCVD;
>>>  }
>>>
>>> +/* Called with rcu_read_lock and BH disabled. */
>>> +static int gre_err(struct sk_buff *skb, u32 info,
>>> +                  const struct tnl_ptk_info *tpi)
>>> +{
>>> +       struct ovs_net *ovs_net;
>>> +       struct vport *vport;
>>> +
>>> +       ovs_net = net_generic(dev_net(skb->dev), ovs_net_id);
>>> +       vport = rcu_dereference(ovs_net->vport_net.gre_vport);
>>> +       if (unlikely(!vport))
>>> +               return PACKET_REJECT;
>>> +       else
>>> +               return PACKET_RCVD;
>>
>>Sorry, I forgot to say this before - if we receive the packet then we
>>should also call consume_skb() on it.
>
> Maybe there is no need to call consume_skb()? The icmp_rcv() would
> call kfree_skb() for us. I also checked the ipgre_err(), it return
> PACKET_RCVD without call consume_skb() too.

Thanks, you are right. I applied your patch as is.
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