Re: KASAN: use-after-free Read in btrfs_scan_one_device

[David Sterba]

On Wed, Sep 30, 2020 at 06:57:56PM +0200, David Sterba wrote:
> On Sun, Sep 20, 2020 at 07:12:14AM -0700, syzbot wrote:
> > Hello,
> > 
> > syzbot found the following issue on:
> > 
> > HEAD commit:    eb5f95f1 Merge tag 's390-5.9-6' of git://git.kernel.org/pu..
> > git tree:       upstream
> > console output: https://syzkaller.appspot.com/x/log.txt?x=10a0a8bb900000
> > kernel config:  https://syzkaller.appspot.com/x/.config?x=ffe85b197a57c180
> > dashboard link: https://syzkaller.appspot.com/bug?extid=582e66e5edf36a22c7b0
> > compiler:       gcc (GCC) 10.1.0-syz 20200507
> > 
> > Unfortunately, I don't have any reproducer for this issue yet.
> > 
> > IMPORTANT: if you fix the issue, please add the following tag to the commit:
> > Reported-by: syzbot+582e66e5edf36a22c7b0@xxxxxxxxxxxxxxxxxxxxxxxxx
> 
> #syz fix: btrfs: fix overflow when copying corrupt csums for a message

Johannes spotted that this is not the right fix for this report, I don't
know how to tell syzbot to revert the 'fix:' command, there isn't
'unfix' (like there's 'undup').