From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jarek Poplawski <jarkao2@gmail.com>
Subject: Re: Kernel panic eth2 mirred redirect to ifb0
Date: Sun, 19 Dec 2010 23:15:50 +0100
Message-ID: <4D0E8416.2030100@gmail.com>
References: <4D0DEDF9.7020102@itcare.pl> <1292773433.18869.153.camel@edumazet-laptop> <4D0E2E52.3090802@itcare.pl> <AANLkTimMY3D_HssWb=Sw=b3tsxEKACk2QUzFzi-HaC-J@mail.gmail.com> <4D0E6C6D.10806@itcare.pl>
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Cc: Changli Gao <xiaosuo@gmail.com>,
	Eric Dumazet <eric.dumazet@gmail.com>,
	Linux Network Development list <netdev@vger.kernel.org>
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Pawe=C5=82 Staszewski wrote:
> W dniu 2010-12-19 17:22, Changli Gao pisze:
>> 2010/12/20 Pawe=C5=82 Staszewski<pstaszewski@itcare.pl>:
>>> W dniu 2010-12-19 16:43, Eric Dumazet pisze:
>>>> Unfortunately, we miss the start of panic messages. Could you try =
to
>>>> get
>>>> them ?
>>>>
>>> In attached images
>>>
>> It seems the kernel panic at:
>>
>>          if (skb_shared(skb))
>>                  BUG();
>>
>> in pskb_expand_head().
>>
>> It maybe related to my patch:
>> http://git.kernel.org/?p=3Dlinux/kernel/git/davem/net-next-2.6.git;a=
=3Dcommitdiff;h=3D210d6de78c5d7c785fc532556cea340e517955e1
>>
>>
>> You can try to revert it and test again.
>>
>> However, the bug is a misuse of pskb_expand_head().
>>
> patching file net/sched/act_mirred.c
> Hunk #1 FAILED at 169.
> Hunk #2 succeeded at 195 (offset 10 lines).
> 1 out of 2 hunks FAILED -- saving rejects to file
> net/sched/act_mirred.c.rej
>=20
> ***************
> *** 169,181 ****
>                 goto out;
>         }
>=20
> -       at =3D G_TC_AT(skb->tc_verd);
> -       skb2 =3D skb_act_clone(skb, GFP_ATOMIC, m->tcf_action);
>         if (skb2 =3D=3D NULL)
>                 goto out;
>=20
>         m->tcf_bstats.bytes +=3D qdisc_pkt_len(skb2);
>         m->tcf_bstats.packets++;
>         if (!(at & AT_EGRESS)) {
>                 if (m->tcfm_ok_push)
>                         skb_push(skb2, skb2->dev->hard_header_len);
> --- 169,181 ----
>                 goto out;
>         }
>=20
> +       skb2 =3D skb_act_clone(skb, GFP_ATOMIC);
>         if (skb2 =3D=3D NULL)
>                 goto out;
>=20
>         m->tcf_bstats.bytes +=3D qdisc_pkt_len(skb2);
>         m->tcf_bstats.packets++;
> +       at =3D G_TC_AT(skb->tc_verd);
>         if (!(at & AT_EGRESS)) {
>                 if (m->tcfm_ok_push)
>                         skb_push(skb2, skb2->dev->hard_header_len);
>=20
> for sch_generic.h was ok.

Should be enough to try after reverting this sch_generic.h change only.

Jarek P.