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Date:   Sat, 8 May 2021 16:46:57 +0200
From:   Florian Westphal <fw@strlen.de>
To:     Dmitry Vyukov <dvyukov@google.com>
Cc:     syzbot <syzbot+154bd5be532a63aa778b@syzkaller.appspotmail.com>,
        coreteam@netfilter.org, David Miller <davem@davemloft.net>,
        Florian Westphal <fw@strlen.de>,
        Jozsef Kadlecsik <kadlec@netfilter.org>,
        Jakub Kicinski <kuba@kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        netdev <netdev@vger.kernel.org>,
        NetFilter <netfilter-devel@vger.kernel.org>,
        Pablo Neira Ayuso <pablo@netfilter.org>,
        syzkaller-bugs <syzkaller-bugs@googlegroups.com>
Subject: Re: [syzbot] WARNING in __nf_unregister_net_hook (4)
Message-ID: <20210508144657.GC4038@breakpoint.cc>
References: <0000000000008ce91e05bf9f62bc@google.com>
 <CACT4Y+a6L_x22XNJVX+VYY-XKmLQ0GaYndCVYnaFmoxk58GPgw@mail.gmail.com>
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Dmitry Vyukov <dvyukov@google.com> wrote:
> > IMPORTANT: if you fix the issue, please add the following tag to the commit:
> > Reported-by: syzbot+154bd5be532a63aa778b@syzkaller.appspotmail.com
> 
> Is this also fixed by "netfilter: arptables: use pernet ops struct
> during unregister"?
> The warning is the same, but the stack is different...

No, this is a different bug.

In both cases the caller attempts to unregister a hook that the core
can't find, but in this case the caller is nftables, not arptables.