netdev - Re: [net-next PATCH v2 0/8] UDP GSO Segmentation clean-ups

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Date:   Mon, 7 May 2018 11:02:18 -0700
From:   Alexander Duyck <alexander.duyck@...il.com>
To:     Willem de Bruijn <willemdebruijn.kernel@...il.com>
Cc:     Network Development <netdev@...r.kernel.org>,
        Willem de Bruijn <willemb@...gle.com>,
        David Miller <davem@...emloft.net>
Subject: Re: [net-next PATCH v2 0/8] UDP GSO Segmentation clean-ups

On Sat, May 5, 2018 at 3:06 AM, Willem de Bruijn
<willemdebruijn.kernel@...il.com> wrote:
> On Fri, May 4, 2018 at 8:28 PM, Alexander Duyck
> <alexander.duyck@...il.com> wrote:
>> This patch set addresses a number of issues I found while sorting out
>> enabling UDP GSO Segmentation support for ixgbe/ixgbevf. Specifically there
>> were a number of issues related to the checksum and such that seemed to
>> cause either minor irregularities or kernel panics in the case of the
>> offload request being allowed to traverse between name spaces.
>
> Were you able to traverse GSO packets between network namespace before
> adding to NETIF_F_GSO_SOFTWARE? It does appear that veth includes
> NETIF_F_GSO_ENCAP_ALL, which also allows GSO.

Without that change the tunnel wouldn't pass the requests between
namespaces. However with it I was able to easily test the software
checksum code as otherwise the socket was returning EIO when the
hardware checksum was disabled.

> In either case, it should not be possible for GSO packets to arrive on a veth
> device, as that can result in queuing the GSO packet to a recipient socket.
> In this regard veth is like loopback and must exclude GSO support.
>
> I'll take a look.

I suspect it was probably sending veth UDP segmentation offload
requests. For now I can probably drop he patch that was adding it and
it can be added later to individual drivers if needed.

Thanks.

- Alex