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Date:   Mon, 22 Apr 2019 19:27:32 +0200
From:   Florian Westphal <fw@strlen.de>
To:     Andreas Hartmann <andihartmann@01019freenet.de>
Cc:     Florian Westphal <fw@strlen.de>,
        Pablo Neira Ayuso <pablo@netfilter.org>,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH 4.19 13/99] netfilter: nf_conncount: fix argument order
 to find_next_bit
Message-ID: <20190422172732.sneybhuwrreb7g2u@breakpoint.cc>
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 <20190121134914.421023706@linuxfoundation.org>
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Andreas Hartmann <andihartmann@01019freenet.de> wrote:
> Since 4.19.17, I'm facing problems during streaming of videos I've never seen before. This means:
> 
> - video from internet stutters although enough data flow can be seen in bmon.
> - gpu is locked:
>   radeon 0000:0a:00.0: ring 0 stalled for more than 14084msec
>   radeon 0000:0a:00.0: GPU lockup (current fence id 0x0000000000053ed7 last fence id 0x0000000000053f0f on ring 0)
> - The connection of videos streamed locally by the machine for a TV suddenly breaks (upnp - serviio as server).
> 
> After very long time of testing, I detected, that removing the complete patch series for 4.19.17 regarding netfilter: nf_conncount makes the problem disappear.
> 
> Please remove / fix this patchset!

The state in 4.19.y is same as in mainline.
Could you at least tell us how you're using nf_conncount (nf/iptables
rules)?

Could you test with debugging (KASAN, CONFIG_PROVE_RCU etc). enabled?

I'm really surprised about this report, before the backport nf_conncount
caused frequent kernel crashes, how does reverting even work...?