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Message-ID: <871cbef1-d1e2-78a0-7efe-2925bfe90110@linux.ibm.com>
Date:   Thu, 24 Mar 2022 09:11:33 +0100
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Subject: Re: [syzbot] BUG: unable to handle kernel NULL pointer dereference in
 __tcp_transmit_skb
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To:     Eric Dumazet <edumazet@google.com>,
        syzbot <syzbot+090d23ddbd5cd185c2e0@syzkaller.appspotmail.com>
Cc:     Andrii Nakryiko <andrii@kernel.org>,
        Alexei Starovoitov <ast@kernel.org>, bpf <bpf@vger.kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        David Miller <davem@davemloft.net>,
        David Ahern <dsahern@kernel.org>,
        John Fastabend <john.fastabend@gmail.com>,
        Martin KaFai Lau <kafai@fb.com>,
        KP Singh <kpsingh@kernel.org>,
        Jakub Kicinski <kuba@kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        netdev <netdev@vger.kernel.org>, Paolo Abeni <pabeni@redhat.com>,
        Song Liu <songliubraving@fb.com>,
        syzkaller-bugs <syzkaller-bugs@googlegroups.com>,
        Yonghong Song <yhs@fb.com>,
        Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>,
        Wenjia Zhang <wenjia@linux.ibm.com>,
        Thorsten Winkler <twinkler@linux.ibm.com>,
        Alexandra Winter <wintera@linux.ibm.com>
References: <000000000000acf1e405daebb7c7@google.com>
 <CANn89iKMWp3o7ZS9dL+6GgWR-tr2rOvMKdKxb1=aDmhLB7mFrw@mail.gmail.com>
From:   Karsten Graul <kgraul@linux.ibm.com>
Organization: IBM Deutschland Research & Development GmbH
In-Reply-To: <CANn89iKMWp3o7ZS9dL+6GgWR-tr2rOvMKdKxb1=aDmhLB7mFrw@mail.gmail.com>
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On 24/03/2022 02:41, Eric Dumazet wrote:
> On Wed, Mar 23, 2022 at 5:13 PM syzbot
> <syzbot+090d23ddbd5cd185c2e0@syzkaller.appspotmail.com> wrote:
>>
>> Hello,
>>
>> syzbot found the following issue on:
>>
>> HEAD commit:    36c2e31ad25b net: geneve: add missing netlink policy and s..
>> git tree:       net-next
>> console output: https://syzkaller.appspot.com/x/log.txt?x=17c308a5700000
>> kernel config:  https://syzkaller.appspot.com/x/.config?x=4a15e2288cf165c9
>> dashboard link: https://syzkaller.appspot.com/bug?extid=090d23ddbd5cd185c2e0
>> compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
>> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=171eadbd700000
>> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=12cacda3700000
>>
>> IMPORTANT: if you fix the issue, please add the following tag to the commit:
>> Reported-by: syzbot+090d23ddbd5cd185c2e0@syzkaller.appspotmail.com
>>
> 
> AF_SMC does not handle TCP_REPAIR properly.
> 
> Look at commit d9e4c129181004e ("mptcp: only admit explicitly
> supported sockopt") for an equivalent bug/fix.

Got it, we will fix that.