WARNING in exfat_bdev_read

[syzbot]

syzbot suspects this bug was fixed by commit:

commit 5f33771fb0ac484d6e8cc34cb1e27c37442cd0db
Author: Namjae Jeon <namjae.jeon at samsung.com>
Date:   Fri Jan 3 01:13:45 2020 +0000

    staging: exfat: add STAGING prefix to config names

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=1407f818100000
start commit:   32ef9553 Merge tag 'fsnotify_for_v5.5-rc1' of git://git.ke..
git tree:       upstream
kernel config:  https://syzkaller.appspot.com/x/.config?x=ff560c3de405258c
dashboard link: https://syzkaller.appspot.com/bug?extid=1930da7118e99b06e4ab
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=10e208a6e00000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=11f83882e00000

If the result looks correct, please mark the bug fixed by replying with:

#syz fix: staging: exfat: add STAGING prefix to config names

For information about bisection process see: https://goo.gl/tpsmEJ#bisection