Comment 16 for bug 1711407

With https://github.com/fho/docker-samba-loop I was able to reproduce kernel Oopses on a clean Ubuntu 16.0.4 installation with:

- linux-image-4.10.0-32-generic=4.10.0-32.36~16.04.1
- linux-image-4.11.0-14-generic=4.11.0-14.20~16.04.1

On 4.11.0-14 it was much harder to reproduce. Sometimes only a warning
happened, 1x time I was able to produce an Oops with
https://github.com/fho/docker-samba-loop/commits/more_stress
But I don't know if the changes in the branch made it more likely to happen or
if it was only a coincidence.

The kernel message:
  unregister_netdevice: waiting for lo to become free. Usage count = 1
shows up, some minutes later the oops and/or warning happens.

In a different scenario were the Ubuntu 16.04 servers were running multiple docker containers with Nginx or small network applications in parallel, I was also able to reproduce the kernel Oopses also on:

- linux-image-4.10.0-1004-gcp
- linux-image-4.4.0-93-generic
- linux-image-4.11.0-14-generic
- linux-image-4.12.10-041210-generic=4.12.10-041210.20170830

I haven't tried again to reproduce it with those kernels on a clean Ubuntu
installation and unfortunately didn't kept the kernel logs.

Kernel logs can be found in the attached file.