netdev - Re: [PATCH net] vti6: remove !skb->ignore_df check from vti6

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Date:   Wed, 29 Aug 2018 17:52:00 -0700 (PDT)
From:   David Miller <davem@...emloft.net>
To:     alexey.kodanev@...cle.com
Cc:     netdev@...r.kernel.org, steffen.klassert@...unet.com
Subject: Re: [PATCH net] vti6: remove !skb->ignore_df check from vti6_xmit()

From: Alexey Kodanev <alexey.kodanev@...cle.com>
Date: Thu, 23 Aug 2018 19:49:54 +0300

> Before the commit d6990976af7c ("vti6: fix PMTU caching and reporting
> on xmit") '!skb->ignore_df' check was always true because the function
> skb_scrub_packet() was called before it, resetting ignore_df to zero.
> 
> In the commit, skb_scrub_packet() was moved below, and now this check
> can be false for the packet, e.g. when sending it in the two fragments,
> this prevents successful PMTU updates in such case. The next attempts
> to send the packet lead to the same tx error. Moreover, vti6 initial
> MTU value relies on PMTU adjustments.
> 
> This issue can be reproduced with the following LTP test script:
>     udp_ipsec_vti.sh -6 -p ah -m tunnel -s 2000
> 
> Fixes: ccd740cbc6e0 ("vti6: Add pmtu handling to vti6_xmit.")
> Signed-off-by: Alexey Kodanev <alexey.kodanev@...cle.com>

Applied and queued up for -stable, thank you.