syzbot has bisected this bug to:
commit dee160df820de41ff2f59a715643680822a0ab06
Author: NeilBrown <neilb@xxxxxxxx>
Date: Mon Nov 5 01:30:47 2018 +0000
locks: use properly initialized file_lock when unlocking.
bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=13f39fd7200000
start commit: dee160df locks: use properly initialized file_lock when un..
git tree: linux-next
final crash: https://syzkaller.appspot.com/x/report.txt?x=100b9fd7200000
console output: https://syzkaller.appspot.com/x/log.txt?x=17f39fd7200000
kernel config: https://syzkaller.appspot.com/x/.config?x=caa433e1c8778437
dashboard link: https://syzkaller.appspot.com/bug?extid=83e12cf81d2c14842146
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=15bd9447400000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1121d82b400000
Reported-by: syzbot+83e12cf81d2c14842146@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: dee160df ("locks: use properly initialized file_lock when
unlocking.")
