Re: unregister_netdevice: waiting for DEV to become free (2)

[syzbot]

syzbot has found a reproducer for the following crash on:

HEAD commit:    d7857ae43dcc Add linux-next specific files for 20180817
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=13c72fce400000
kernel config:  https://syzkaller.appspot.com/x/.config?x=4b10cd1ea76bb092
dashboard link: https://syzkaller.appspot.com/bug?extid=30209ea299c09d8785c9
compiler:       gcc (GCC) 8.0.1 20180413 (experimental)
syzkaller repro:https://syzkaller.appspot.com/x/repro.syz?x=15df679a400000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=15242741400000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+30209ea299c09d8785c9@xxxxxxxxxxxxxxxxxxxxxxxxx

IPVS: stopping master sync thread 4657 ...
IPVS: stopping master sync thread 4663 ...
IPVS: sync thread started: state = MASTER, mcast_ifn = syz_tun, syncid = 0,  
id = 0
IPVS: sync thread started: state = MASTER, mcast_ifn = syz_tun, syncid = 0,  
id = 0
IPVS: stopping master sync thread 4664 ...
unregister_netdevice: waiting for lo to become free. Usage count = 1