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Subject: Re: CAKE and r8169 cause panic on upload in v4.19
To:     Oleksandr Natalenko <oleksandr@natalenko.name>,
        Dave Taht <dave.taht@gmail.com>,
        "David S. Miller" <davem@davemloft.net>
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
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From:   Heiner Kallweit <hkallweit1@gmail.com>
Message-ID: <1beabdd3-dbac-de8a-07b0-d0788b1dbc38@gmail.com>
Date:   Sat, 27 Oct 2018 15:43:28 +0200
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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.