Re: bridge/netfilter: regression in 2.6.39.1

From: Eric Dumazet
Date: Fri Jun 03 2011 - 15:34:12 EST


Le vendredi 03 juin 2011 Ã 21:21 +0200, Alexander Holler a Ãcrit :
> Hello,
>
> I'm getting a oops in the bridge code in br_change_mtu() with 2.6.39.1.
> The patch below seems to fix that.
>
> I'm not sure about the usage of dst_cow_metrics_generic() in
> fake_dst_ops, but after having a quick look at it seems to be ok to use
> that here.
>
> Regards,
>
> Alexander
>
> -----
> From 3c1d5951af73389798afeea672ec224e195b8e8d Mon Sep 17 00:00:00 2001
> From: Alexander Holler <holler@xxxxxxxxxxxxx>
> Date: Fri, 3 Jun 2011 20:43:06 +0200
> Subject: [PATCH] bridge: add dst_cow_metrics_generic to fake_dst_ops
>
> Commit 42923465fb8d025a2b5153f2e7ab1e6e1058bf00 does here what it
> should prevent, it introduces NULL a dereference.
>

I cant find this commit in known trees. Could you give the real commit
id and its title ?

> The above commit uses dst_init_metrics() which sets the metrics as
> read only. As result br_change_mtu() dies in dst_metric_set()
> which calls dst_metrics_write_ptr() which calls
> dst->ops->cow_metrics() if the metrics are read only.
> ---
> net/bridge/br_netfilter.c | 1 +
> 1 files changed, 1 insertions(+), 0 deletions(-)
>
> diff --git a/net/bridge/br_netfilter.c b/net/bridge/br_netfilter.c
> index 5f9c091..de982a1 100644
> --- a/net/bridge/br_netfilter.c
> +++ b/net/bridge/br_netfilter.c
> @@ -107,6 +107,7 @@ static void fake_update_pmtu(struct dst_entry *dst,
> u32 mtu)
> static struct dst_ops fake_dst_ops = {
> .family = AF_INET,
> .protocol = cpu_to_be16(ETH_P_IP),
> + .cow_metrics = dst_cow_metrics_generic,
> .update_pmtu = fake_update_pmtu,
> };
>

Your patch is mangled (white spaces instead of tabulations)

Thanks


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