From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jovi Zhangwei <jovi@cloudflare.com>
Subject: Re: kernel warning in tcp_fragment
Date: Mon, 10 Aug 2015 14:53:11 -0700
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Cc: Martin KaFai Lau <kafai@fb.com>,
	Eric Dumazet <edumazet@google.com>,
	Netdev <netdev@vger.kernel.org>,
	David Miller <davem@davemloft.net>,
	Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>,
	James Morris <jmorris@namei.org>,
	Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>,
	Patrick McHardy <kaber@trash.net>,
	FB Kernel Team <kernel-team@fb.com>
To: Neal Cardwell <ncardwell@google.com>
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Hi Neal,

Great thanks for your reply, we will arrange testing against that patch.

On Mon, Aug 10, 2015 at 11:35 AM, Neal Cardwell <ncardwell@google.com> wrote:
> On Mon, Aug 10, 2015 at 2:10 PM, Jovi Zhangwei <jovi@cloudflare.com> wrote:
>>
>> Ping?
>>
>> We saw a lot of this warnings in our production system. It would be
>> great appreciate if someone can give us the fix on this warnings. :)
>
> What is your net.ipv4.tcp_mtu_probing setting? If 1, have you tried
> setting it to 0? Previous reports (
> https://patchwork.ozlabs.org/patch/480882/ ) have shown that this gets
> rid of at least one source of the warning. So that would provide a
> useful data point.
>
> Separately, you could also try the attached patch. This is against
> 3.14.39. It tries to attack a different possible source of this
> warning. Please let us know if that patch helps.
>
> Thanks!
>
> neal