Re: bridge/netfilter: regression in 2.6.39.1

Am 03.06.2011 21:34, schrieb Eric Dumazet:

Le vendredi 03 juin 2011 à 21:21 +0200, Alexander Holler a écrit :

quoted

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<redacted>
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 ?

quoted

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)

The patch had a tab, so either c&p failed or something else removed the 
tab. Maybe Thunderbird, don't know. Normally I'm using git send-email.

If someone gives a feedback about the content and not the style, I'm 
willing to send a nice patch which too includes the forgotten Signed-off-by.

Regards,

Alexander