From: Florian Westphal <fw-HFFVJYpyMKqzQB+pC5nmwQ@public.gmane.org>
To: David Miller <davem-fT/PcQaiUtIeIZ0/mPfg9Q@public.gmane.org>
Cc: dev-yBygre7rU0TnMu66kgdUjQ@public.gmane.org,
netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
fw-HFFVJYpyMKqzQB+pC5nmwQ@public.gmane.org,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
edumazet-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org,
xiyou.wangcong-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org,
koct9i-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org
Subject: Re: [PATCH v2] net: preserve IP control block during GSO segmentation
Date: Thu, 14 Jan 2016 00:36:28 +0100 [thread overview]
Message-ID: <20160113233628.GA10507@breakpoint.cc> (raw)
In-Reply-To: <20160113.155112.119405358547782630.davem-fT/PcQaiUtIeIZ0/mPfg9Q@public.gmane.org>
David Miller <davem@davemloft.net> wrote:
> From: Konstantin Khlebnikov <koct9i@gmail.com>
> Date: Fri, 08 Jan 2016 15:21:46 +0300
>
> > Skb_gso_segment() uses skb control block during segmentation.
> > This patch adds 32-bytes room for previous control block which
> > will be copied into all resulting segments.
> >
> > This patch fixes kernel crash during fragmenting forwarded packets.
> > Fragmentation requires valid IP CB in skb for clearing ip options.
> > Also patch removes custom save/restore in ovs code, now it's redundant.
> >
> > Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com>
> > Link: http://lkml.kernel.org/r/CALYGNiP-0MZ-FExV2HutTvE9U-QQtkKSoE--KN=JQE5STYsjAA@mail.gmail.com
>
> If this works I definitely prefer this approach to the other patch
> where the CB is copied back and forth.
I quite frankly don't care and just like you to apply one or the other;
use coin toss if needed :-}
I would prefer to use a on-stack state since there is no need to
use skb->cb (no queueing) but when I gave it a try it got out of hand
rather quick :-/
Anyway Konstantins approach is safe since we only need this in
ovs/ip forward + nfnetlink_queue cases and in all of these there is
enough room at the cb end (for now at least).
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next prev parent reply other threads:[~2016-01-13 23:36 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-08 12:21 [PATCH v2] net: preserve IP control block during GSO segmentation Konstantin Khlebnikov
2016-01-13 20:51 ` David Miller
[not found] ` <20160113.155112.119405358547782630.davem-fT/PcQaiUtIeIZ0/mPfg9Q@public.gmane.org>
2016-01-13 23:36 ` Florian Westphal [this message]
[not found] ` <20160113233628.GA10507-E0PNVn5OA6ohrxcnuTQ+TQ@public.gmane.org>
2016-01-14 23:22 ` Hannes Frederic Sowa
2016-01-15 19:35 ` David Miller
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