From mboxrd@z Thu Jan  1 00:00:00 1970
From: Eric Dumazet <eric.dumazet@gmail.com>
Subject: Re: bridge/netfilter: regression in 2.6.39.1
Date: Mon, 06 Jun 2011 15:18:12 +0200
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Cc: Alexander Holler <holler@ahsoftware.de>,
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	Herbert Xu <herbert@gondor.apana.org.au>,
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To: Neil Horman <nhorman@tuxdriver.com>
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Le lundi 06 juin 2011 =C3=A0 09:13 -0400, Neil Horman a =C3=A9crit :

> Ok, this makes sense to me now, thanks.  The change to the dst inital=
ization to
> mark our fake routing table as read only means we need a cow_metrics =
method to
> copy the metrics before we we can compete the dst_metric_set in br_ch=
ange_mtu.
> Thats fine, but given that its really a fake routing table with only =
one dst
> entry which (I think) is only written under the rtnl lock, why not ju=
st modify
> the dst_init_metrics call so that its not marked as read-only?

It _is_ read-only, its even a "const", so if you do that you'll trap if
kernel const pages are RO

Please check commit 0972ddb237 for a proper way to deal with this.