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From:   Vegard Nossum <vegard.nossum@gmail.com>
Date:   Mon, 24 Jan 2022 14:00:01 +0100
Message-ID: <CAOMGZ=FdNnYS8wa8gViXiMrvtrESzPURfW8Pofx0y9BNk+PEZw@mail.gmail.com>
Subject: Re: [syzbot] BUG: unable to handle kernel NULL pointer dereference in unix_shutdown
To:     syzbot <syzbot+cd7ceee0d3b5892f07af@syzkaller.appspotmail.com>
Cc:     Rao.Shoaib@oracle.com, andrii@kernel.org, ast@kernel.org,
        bpf@vger.kernel.org, cong.wang@bytedance.com, daniel@iogearbox.net,
        "David S. Miller" <davem@davemloft.net>, john.fastabend@gmail.com,
        kafai@fb.com, kpsingh@kernel.org, kuba@kernel.org,
        LKML <linux-kernel@vger.kernel.org>,
        Linux Netdev List <netdev@vger.kernel.org>,
        songliubraving@fb.com, syzkaller-bugs@googlegroups.com,
        Al Viro <viro@zeniv.linux.org.uk>, yhs@fb.com
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On Sat, 21 Aug 2021 at 17:19, syzbot
<syzbot+cd7ceee0d3b5892f07af@syzkaller.appspotmail.com> wrote:
>
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit:    9803fb968c8c Add linux-next specific files for 20210817
> git tree:       linux-next
> console output: https://syzkaller.appspot.com/x/log.txt?x=1727c65e300000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=681282daead30d81
> dashboard link: https://syzkaller.appspot.com/bug?extid=cd7ceee0d3b5892f07af
> compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.1
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=13fb6ff9300000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=15272861300000
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+cd7ceee0d3b5892f07af@syzkaller.appspotmail.com
>
> BUG: kernel NULL pointer dereference, address: 0000000000000000

Looks like this was only ever hit in linux-next and fixed before it
got to mainline? Anyway, I can confirm the following patch fixes the
issue:

#syz fix: af_unix: Fix NULL pointer bug in unix_shutdown


Vegard