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Message-ID: <4837d1401e1610764eeea7446280de87d51912f6.camel@redhat.com>
Subject: Re: [syzbot] [mptcp?] WARNING in mptcp_check_listen_stop
From:   Paolo Abeni <pabeni@redhat.com>
To:     syzbot <syzbot+5a01c3a666e726bc8752@syzkaller.appspotmail.com>,
        davem@davemloft.net, edumazet@google.com, kuba@kernel.org,
        linux-kernel@vger.kernel.org, martineau@kernel.org,
        matttbe@kernel.org, mptcp@lists.linux.dev, netdev@vger.kernel.org,
        syzkaller-bugs@googlegroups.com
Date:   Thu, 14 Dec 2023 16:18:27 +0100
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References: <000000000000703582060c68aeab@google.com>
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On Wed, 2023-12-13 at 10:53 -0800, syzbot wrote:
> syzbot has found a reproducer for the following issue on:
>=20
> HEAD commit:    2513974cc3e1 Merge branch 'stmmac-bug-fixes'
> git tree:       net
> console+strace: https://syzkaller.appspot.com/x/log.txt?x=3D116337fae8000=
0
> kernel config:  https://syzkaller.appspot.com/x/.config?x=3Db50bd31249191=
be8
> dashboard link: https://syzkaller.appspot.com/bug?extid=3D5a01c3a666e726b=
c8752
> compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for D=
ebian) 2.40
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=3D1119061ee80=
000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=3D110ca006e8000=
0

It looks like tcp_diag_destroy is closing the listener subflow, while
the mptcp stack is not expecting anyone to touch it while in listener
status. I guess we can relax the mptcp_check_listen_stop checks.

/P=20