/etc/rc6.d/K20virtualbox hangs on reboot if a VM is running

[Marius Gedminas]

I had a Vagrant virtual machine running in the background, configured with two network interfaces: NAT and host-only.
I tried to reboot my laptop. It got stuck in the shutdown phase.

Pressing Esc let me see the following kernel messages:

    unregister_netdevice: waiting for vboxnet0 to become free. Usage count = 1

repeated every few seconds.

I got bored of waiting after a few minutes and tried most of the SysRq keys. Unfortunately show-task-states(t) and show-blocked-tasks(w) are disabled by default on Ubuntu, as are terminate-all-tasks(e) and kill-all-tasks(i). I tried SAK(k) and saw it killing some tasks with evocative names

    K20virtualbox
    rmmod

Following that I completed the reboot with Alt+SysRq+S,U,B.

vboxnet0 is used for the host-only networking. It's plausible that VMs that only use NAT networking do not cause problems for the init script.

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: virtualbox 4.3.10-dfsg-1
ProcVersionSignature: Ubuntu 3.13.0-36.63-generic 3.13.11.6
Uname: Linux 3.13.0-36-generic x86_64
ApportVersion: 2.14.1-0ubuntu3.4
Architecture: amd64
CurrentDesktop: GNOME
Date: Thu Sep 25 13:21:47 2014
EcryptfsInUse: Yes
InstallationDate: Installed on 2012-07-25 (791 days ago)
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Release amd64 (20120425)
SourcePackage: virtualbox
UpgradeStatus: Upgraded to trusty on 2014-04-18 (160 days ago)

[Marius Gedminas (mgedmin)]

This can be reproduced by starting a Vagrant virtual machine and attempting to run

    sudo service virtualbox stop

The init script loops forever. (I waited more than an hour once.)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Gianfranco Costamagna (costamagnagianfranco)]

This kind of hangs should be fixed in 4.3.24, please test the vivid package and open an upstream issue if the bug is still there!

thanks

[Gianfranco Costamagna (costamagnagianfranco)]

upstream reference: https://www.virtualbox.org/ticket/12264