[OpenWrt-Devel] [BUG] kernel crash in br_netfilter

Felix Fietkau nbd at openwrt.org
Tue Mar 8 06:55:58 EST 2016

On 2016-03-08 12:06, Florian Westphal wrote:
>> My hot-fix to prevent the crash is to instead of passing the skb to NF_HOOK
>> directly pass it to br_handle_local_finish(). But having insufficient insight into
>> what is going on there, this is fighting the symptoms rather than solving the root
>> cause. Maybe it is even better to drop patch 120 (not tested yet)?
> Sorry, I don't know why this patch was not merged upstream and do not know why its
> in openwrt.
This patch exists, because it's otherwise impossible to bridge a client
mode (4addr) WLAN interface when encryption is enabled.

wpa_supplicant needs to receive EAP packets before it will change the
operstate to allow the bridge and the rest of the network stack to do
their thing.

This used to work in a while back, and I think it got broken by this

commit 576eb62598f10c8c7fd75703fe89010cdcfff596
Author: stephen hemminger <shemminger at vyatta.com>
Date:   Fri Dec 28 18:15:22 2012 +0000

 bridge: respect RFC2863 operational state

 The bridge link detection should follow the operational state
 of the lower device, rather than the carrier bit. This allows devices
 like tunnels that are controlled by userspace control plane to work
 with bridge STP link management.

 Signed-off-by: Stephen Hemminger <shemminger at vyatta.com>
 Reviewed-by: Flavio Leitner <fbl at redhat.com>
 Signed-off-by: David S. Miller <davem at davemloft.net>

Back then I proposed a patch for upstream inclusion, got some feedback,
Stephen sent me this patch and I fixed it up a bit and re-submitted it.
I think it got lost somewhere in the process and after that I lost track
and didn't get around to re-submitting it.

So we kept the patch in OpenWrt because as far as I know, the regression
still exists in current kernels.

- Felix
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