Re: WARNING in kernfs_create_dir_ns

[syzbot]

syzbot has bisected this bug to:

commit 7f38abf220e2c800a2c451372e9f07ed5fd0ea49
Author: Hongjie Fang <hongjiefang@xxxxxxxxxxxx>
Date:   Tue Jul 31 02:55:09 2018 +0000

    mmc: core: improve reasonableness of bus width setting for HS400es

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=129d6755a00000
start commit:   72825454 Merge branch 'x86-urgent-for-linus' of git://git...
git tree:       upstream
final crash:    https://syzkaller.appspot.com/x/report.txt?x=119d6755a00000
console output: https://syzkaller.appspot.com/x/log.txt?x=169d6755a00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=9a31528e58cc12e2
dashboard link: https://syzkaller.appspot.com/bug?extid=38f5d5cf7ae88c46b11a
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=12a6c439a00000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1353c323a00000

Reported-by: syzbot+38f5d5cf7ae88c46b11a@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: 7f38abf220e2 ("mmc: core: improve reasonableness of bus width  
setting for HS400es")

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