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Message-ID: <57fc3806-86c6-b1b2-4c44-083b1b7afc8b@gmail.com>
Date:   Sat, 19 Mar 2022 21:23:06 +0300
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Subject: Re: [syzbot] divide error in dbNextAG
Content-Language: en-US
To:     syzbot <syzbot+46f5c25af73eb8330eb6@syzkaller.appspotmail.com>,
        jfs-discussion@lists.sourceforge.net, linux-kernel@vger.kernel.org,
        shaggy@kernel.org, syzkaller-bugs@googlegroups.com
References: <000000000000b1470105da9622aa@google.com>
From:   Pavel Skripkin <paskripkin@gmail.com>
In-Reply-To: <000000000000b1470105da9622aa@google.com>
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On 3/19/22 21:07, syzbot wrote:
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    09688c0166e7 Linux 5.17-rc8
> git tree:       upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=163e5015700000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=70f75a89c7a0e6bc
> dashboard link: https://syzkaller.appspot.com/bug?extid=46f5c25af73eb8330eb6
> 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=132c1d61700000
> 
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+46f5c25af73eb8330eb6@syzkaller.appspotmail.com
> 
> divide error: 0000 [#1] PREEMPT SMP KASAN
> CPU: 1 PID: 3622 Comm: syz-executor.0 Not tainted 5.17.0-rc8-syzkaller #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
> RIP: 0010:dbNextAG+0xfc/0x5f0 fs/jfs/jfs_dmap.c:602

Looks like malicious fs image with bmp->db_numag == 0.

#syz test:
git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master


With regards,
Pavel Skripkin
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