linux-kernel - [f2fs bug] infinite loop in f2fs_get_meta_page

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Message-ID: <20201007213253.GD1530638@gmail.com>
Date:   Wed, 7 Oct 2020 14:32:53 -0700
From:   Eric Biggers <ebiggers@...nel.org>
To:     Jaegeuk Kim <jaegeuk@...nel.org>
Cc:     chao@...nel.org, linux-f2fs-devel@...ts.sourceforge.net,
        syzkaller-bugs@...glegroups.com, linux-kernel@...r.kernel.org,
        syzbot+ee250ac8137be41d7b13@...kaller.appspotmail.com
Subject: [f2fs bug] infinite loop in f2fs_get_meta_page_nofail()

[moved linux-fsdevel to Bcc]

On Wed, Oct 07, 2020 at 02:18:19AM -0700, syzbot wrote:
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    a804ab08 Add linux-next specific files for 20201006
> git tree:       linux-next
> console output: https://syzkaller.appspot.com/x/log.txt?x=17fe30bf900000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=26c1b4cc4a62ccb
> dashboard link: https://syzkaller.appspot.com/bug?extid=ee250ac8137be41d7b13
> compiler:       gcc (GCC) 10.1.0-syz 20200507
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1336413b900000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=12f7392b900000
> 
> The issue was bisected to:
> 
> commit eede846af512572b1f30b34f9889d7df64c017d4
> Author: Jaegeuk Kim <jaegeuk@...nel.org>
> Date:   Fri Oct 2 21:17:35 2020 +0000
> 
>     f2fs: f2fs_get_meta_page_nofail should not be failed
> 

Jaegeuk, it looks like the loop you added in the above commit doesn't terminate
if the requested page is beyond the end of the device.

- Eric