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From: Eric Dumazet <eric.dumazet@gmail.com>
To: Menglong Dong <menglong8.dong@gmail.com>,
	Eric Dumazet <edumazet@google.com>
Cc: David Miller <davem@davemloft.net>,
	Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>,
	Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>,
	Jakub Kicinski <kuba@kernel.org>, netdev <netdev@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Menglong Dong <dong.menglong@zte.com.cn>
Subject: Re: [PATCH] net: tcp: ratelimit warnings in tcp_recvmsg
Date: Mon, 9 Nov 2020 16:39:24 +0100	[thread overview]
Message-ID: <0ccc35a7-3d19-e37d-52d1-7e900091cc1b@gmail.com> (raw)
In-Reply-To: <CADxym3bP=BRbVAnDCzmrrAyh3i=QO3gAWnUwpU==TskFY-GHYg@mail.gmail.com>



On 11/9/20 3:48 PM, Menglong Dong wrote:
> On Mon, Nov 9, 2020 at 9:36 PM Eric Dumazet <edumazet@google.com> wrote:
>>
>> I do not think this patch is useful. That is simply code churn.
>>
>> Can you trigger the WARN() in the latest upstream version ?
>> If yes this is a serious bug that needs urgent attention.
>>
>> Make sure you have backported all needed fixes into your kernel, if
>> you get this warning on a non pristine kernel.
> 
> Theoretically, this WARN() shouldn't be triggered in any branches.
> Somehow, it just happened in kernel v3.10. This really confused me. I
> wasn't able to keep tracing it, as it is a product environment.
> 
> I notice that the codes for tcp skb receiving didn't change much
> between v3.10 and the latest upstream version, and guess the latest
> version can be triggered too.
> 
> If something is fixed and this WARN() won't be triggered, just ignore me.
> 

Yes, I confirm this WARN() should not trigger.

The bug is not in tcp recvmsg(), that is why you do not see obvious
fix for this issue in 3.10


      reply	other threads:[~2020-11-09 15:39 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-09 13:06 [PATCH] net: tcp: ratelimit warnings in tcp_recvmsg menglong8.dong
2020-11-09 13:36 ` Eric Dumazet
2020-11-09 14:48   ` Menglong Dong
2020-11-09 15:39     ` Eric Dumazet [this message]

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