Re: WARNING in __mmdrop

[syzbot]

syzbot has bisected this bug to:

commit 7f466032dc9e5a61217f22ea34b2df932786bbfc
Author: Jason Wang <jasowang@xxxxxxxxxx>
Date:   Fri May 24 08:12:18 2019 +0000

    vhost: access vq metadata through kernel virtual address

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=149a8a20600000
start commit:   6d21a41b Add linux-next specific files for 20190718
git tree:       linux-next
final crash:    https://syzkaller.appspot.com/x/report.txt?x=169a8a20600000
console output: https://syzkaller.appspot.com/x/log.txt?x=129a8a20600000
kernel config:  https://syzkaller.appspot.com/x/.config?x=3430a151e1452331
dashboard link: https://syzkaller.appspot.com/bug?extid=e58112d71f77113ddb7b
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=10139e68600000

Reported-by: syzbot+e58112d71f77113ddb7b@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: 7f466032dc9e ("vhost: access vq metadata through kernel virtual  
address")

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