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From: Willem de Bruijn <willemdebruijn.kernel@gmail.com>
Date: Mon, 11 Dec 2017 16:56:56 -0500
Message-ID: <CAF=yD-K5EmFr5z2xjmCZCqdprqQ5vmfxV3od9xBnxBQhY+_qgQ@mail.gmail.com>
Subject: Re: [REGRESSION][4.13.y][4.14.y][v4.15.y] net: reduce
 skb_warn_bad_offload() noise
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Joseph Salisbury <joseph.salisbury@canonical.com>,
        Eric Dumazet <edumazet@google.com>, Dmitry Vyukov <dvyukov@google.com>,
        Willem de Bruijn <willemb@google.com>,
        David Miller <davem@davemloft.net>,
        Daniel Borkmann <daniel@iogearbox.net>, jakub.kicinski@netronome.com,
        linux@rasmusvillemoes.dk, John Fastabend <john.fastabend@gmail.com>,
        me@tobin.cc, idosch@mellanox.com,
        Network Development <netdev@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>, stable@vger.kernel.org,
        1715609@bugs.launchpad.net
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On Mon, Dec 11, 2017 at 4:44 PM, Greg Kroah-Hartman
<gregkh@linuxfoundation.org> wrote:
> On Mon, Dec 11, 2017 at 04:25:26PM -0500, Willem de Bruijn wrote:
>> Note that UFO was removed in 4.14 and that skb_warn_bad_offload
>> can happen for various types of packets, so there may be multiple
>> independent bug reports. I'm investigating two other non-UFO reports
>> just now.
>
> Meta-comment, now that UFO is gone from mainline, I'm wondering if I
> should just delete it from 4.4 and 4.9 as well.  Any objections for
> that?  I'd like to make it easy to maintain these kernels for a while,
> and having them diverge like this, with all of the issues around UFO,
> seems like it will just make life harder for myself if I leave it in.
>
> Any opinions?

Some of that removal had to be reverted with commit 0c19f846d582
("net: accept UFO datagrams from tuntap and packet") for VM live
migration between kernels.

Any backports probably should squash that in at the least. Just today
another thread discussed that that patch may not address all open
issues still, so it may be premature to backport at this point.
http://lkml.kernel.org/r/<d71df64e-e65f-4db4-6f2e-c002c15fcbe4@01019freenet.de>