unregister_netdevice: waiting for lo to become free. Usage count = 2
unregister_netdevice: waiting for lo to become free. Usage count = 2
unregister_netdevice: waiting for lo to become free. Usage count = 2
unregister_netdevice: waiting for lo to become free. Usage count = 2
unregister_netdevice: waiting for lo to become free. Usage count = 2
Kernel panic - not syncing: hung_task: blocked tasks
CPU: 1 PID: 881 Comm: khungtaskd Not tainted 4.16.0+ #4
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1b9/0x294 lib/dump_stack.c:113
 panic+0x22f/0x4de kernel/panic.c:183
 check_hung_task kernel/hung_task.c:133 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:190 [inline]
 watchdog+0xc21/0xf60 kernel/hung_task.c:249
 kthread+0x345/0x410 kernel/kthread.c:238
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:411
Dumping ftrace buffer:
   (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..