netdev - Re: BUG:af_packet fails to TX TSO frames

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Message-ID: <23ace6d6-afa7-9a3a-aa61-1245ee6c0498@kot-begemot.co.uk>
Date:   Wed, 11 Oct 2017 19:39:41 +0100
From:   Anton Ivanov <anton.ivanov@...-begemot.co.uk>
To:     Willem de Bruijn <willemdebruijn.kernel@...il.com>,
        Anton Ivanov <anton.ivanov@...bridgegreys.com>
Cc:     Network Development <netdev@...r.kernel.org>,
        David Miller <davem@...emloft.net>
Subject: Re: BUG:af_packet fails to TX TSO frames

The check as now insists that the actual driver supports GSO_ROBUST, 
because we have marked the skb dodgy.

The specific bit which does this check is in net_gso_ok()

Now, lets's see how many Ethernet drivers set GSO_ROBUST.

find drivers/net/ethernet -type f -name "*.[c,h]" -exec grep -H 
GSO_ROBUST {} \;

That returns nothing in 4.x

IMHO - af_packet allocates the skb, does all checks (and extra may be 
added) on the gso, why is this set dodgy in the first place?

A.


On 11/10/17 17:26, Willem de Bruijn wrote:
> On Wed, Oct 11, 2017 at 11:54 AM, Anton Ivanov
> <anton.ivanov@...bridgegreys.com> wrote:
>> It is that patch.
>>
>> I rolled it back and immediately got it to work correctly on a Broadcom
>> Tigon. I can test on all other scenarios, I have tried, I suspect it will
>> come back alive on all of them.
>>
>> I am going to try to trace it through and see exactly where it drops a skb
>> which the card has no issues in accepting.
> It might be in the initialization of gso_type and csum. The virtio_net_hdr
> can encode various combinations of flags that are not allowed by the
> validation logic.
>