From mboxrd@z Thu Jan  1 00:00:00 1970
From: Heiner Kallweit <hkallweit1@gmail.com>
Subject: Re: CAKE and r8169 cause panic on upload in v4.19
Date: Sat, 27 Oct 2018 15:43:28 +0200
Message-ID: <1beabdd3-dbac-de8a-07b0-d0788b1dbc38@gmail.com>
References: <61d09f0db41f269cc9ee13dd68a5c285@natalenko.name>
 <fbd7f0b8-10c8-be17-fce6-327a95d8ea2e@gmail.com>
 <CAA93jw7xoaokrN4oGAyqh6JHAn8nJpUpp_wj-iy+GWNoV-ipNA@mail.gmail.com>
 <b80e6819da8ea74f18b6ec0aaf9128fa@natalenko.name>
Mime-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 7bit
Cc: =?UTF-8?Q?Toke_H=c3=b8iland-J=c3=b8rgensen?= <toke@toke.dk>,
        Jamal Hadi Salim <jhs@mojatatu.com>,
        Cong Wang <xiyou.wangcong@gmail.com>,
        =?UTF-8?B?SmnFmcOtIFDDrXJrbw==?= <jiri@resnulli.us>,
        Linux Kernel Network Developers <netdev@vger.kernel.org>,
        linux-kernel@vger.kernel.org
To: Oleksandr Natalenko <oleksandr@natalenko.name>,
        Dave Taht <dave.taht@gmail.com>,
        "David S. Miller" <davem@davemloft.net>
Return-path: <linux-kernel-owner@vger.kernel.org>
In-Reply-To: <b80e6819da8ea74f18b6ec0aaf9128fa@natalenko.name>
Content-Language: en-US
Sender: linux-kernel-owner@vger.kernel.org
List-Id: netdev.vger.kernel.org

On 26.10.2018 22:54, Oleksandr Natalenko wrote:
> Hi.
> 
> On 26.10.2018 22:25, Dave Taht wrote:
>> Can you repeat your test, disabling gro splitting in cake?
>>
>> the option is "no-split-gso"
> 
> Still panics. Takes a couple of rounds, but panics.
> 
> Moreover, I've stressed my HTB setup like this too for a longer time, and it panics as well. So, at least, now I have a proof this is not a CAKE-specific thing.
> 
> Also, I've stressed it even with noqueue, and the panic is still there. So, this thing is not even sch-specific.
> 
> Next, I've seen GRO bits in the call trace and decided to disable GRO on this NIC. So far, I cannot trigger a panic with GRO disabled even after 20 rounds of speedtest.
> 
> So, must be some generic thing indeed.
> 
In net-next there's the following patch which mentions in the
description that it "eliminates spurious list pointer poisoning":
992cba7e276d ("net: Add and use skb_list_del_init().") 
And spurious list pointer poisoning is what we see here (IMO).

As an idea this patch and a8305bff6852 ("net: Add and use skb_mark_not_on_list().")
from net-next could be applied on top of 4.19. Would be curious
whether it fixes the issue.