syzbot has bisected this bug to:

commit ab92d68fc22f9afab480153bd82a20f6e2533769
Author: Taehee Yoo <ap420073@gmail.com>
Date:   Mon Oct 21 18:47:51 2019 +0000

     net: core: add generic lockdep keys

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=12b54d70e00000
start commit:   60c1769a Add linux-next specific files for 20191028
git tree:       linux-next
final crash:    https://syzkaller.appspot.com/x/report.txt?x=11b54d70e00000
console output: https://syzkaller.appspot.com/x/log.txt?x=16b54d70e00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=cb86688f30db053d
dashboard link: https://syzkaller.appspot.com/bug?extid=8da67f407bcba2c72e6e
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=14d43a04e00000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=16be3b9ce00000

Reported-by: syzbot+8da67f407bcba2c72e6e@syzkaller.appspotmail.com
Fixes: ab92d68fc22f ("net: core: add generic lockdep keys")

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