Re: WARNING: refcount bug in j1939_netdev_start

[syzbot]

syzbot has bisected this bug to:

commit 9d71dd0c70099914fcd063135da3c580865e924c
Author: The j1939 authors <linux-can@xxxxxxxxxxxxxxx>
Date:   Mon Oct 8 09:48:36 2018 +0000

    can: add support of SAE J1939 protocol

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=17100f3ae00000
start commit:   9805a683 Merge branch 'x86-urgent-for-linus' of git://git...
git tree:       upstream
final crash:    https://syzkaller.appspot.com/x/report.txt?x=14900f3ae00000
console output: https://syzkaller.appspot.com/x/log.txt?x=10900f3ae00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=896c87b73c6fcda6
dashboard link: https://syzkaller.appspot.com/bug?extid=afd421337a736d6c1ee6
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=10d713c6e00000

Reported-by: syzbot+afd421337a736d6c1ee6@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: 9d71dd0c7009 ("can: add support of SAE J1939 protocol")

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