Comment 0 for bug 1729637

When running 2 docker containers, one as samba server and another one as samba client that mounts and umounts a smb share a kernel OOps can be triggered on multiple kernels.

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

The scripts to trigger the kernel Oops can be found at: 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-4.4.0-93-generic=4.4.0-93.116~14.04.1
- 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

In a different scenario were 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-4.12.10-041210-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.

The "unregister_netdevice: waiting for lo to become free. Usage count = 1" messages are related to https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1711407 which is handled as separate issue.

According to https://github.com/moby/moby/issues/35068 the crash is fixed by:
https://patchwork.ozlabs.org/patch/801533/
https://patchwork.ozlabs.org/patch/778449/