Re: kernel BUG at lib/string.c:LINE! (5)

[Johannes Thumshirn]

On 16/09/2020 10:19, syzbot wrote:
> syzbot has bisected this issue to:
> 
> commit 3951e7f050ac6a38bbc859fc3cd6093890c31d1c
> Author: Johannes Thumshirn <jthumshirn@xxxxxxx>
> Date:   Mon Oct 7 09:11:01 2019 +0000
> 
>     btrfs: add xxhash64 to checksumming algorithms
> 
> bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=10aadcc5900000
> start commit:   e4c26faa Merge tag 'usb-5.9-rc5' of git://git.kernel.org/p..
> git tree:       upstream
> final oops:     https://syzkaller.appspot.com/x/report.txt?x=12aadcc5900000
> console output: https://syzkaller.appspot.com/x/log.txt?x=14aadcc5900000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=c61610091f4ca8c4
> dashboard link: https://syzkaller.appspot.com/bug?extid=e864a35d361e1d4e29a5
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=177582be900000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=13deb2b5900000
> 
> Reported-by: syzbot+e864a35d361e1d4e29a5@xxxxxxxxxxxxxxxxxxxxxxxxx
> Fixes: 3951e7f050ac ("btrfs: add xxhash64 to checksumming algorithms")
> 
> For information about bisection process see: https://goo.gl/tpsmEJ#bisection
> 

This commit only allowed 8 byte checksums, but d5178578bcd4 ("btrfs: directly
call into crypto framework for checksumming") is the one that was missing the
conversion in btree_readpage_end_io_hook() and a prerequisite for 3951e7f050ac
("btrfs: add xxhash64 to checksumming algorithms"). So I think it makes more 
sense to add d5178578bcd4 to the fixes line.