Comment 29 for bug 561390

In my PPA you'll find a new dmsetup package, could you try it out and see whether it makes things better or worse?

  sudo add-apt-repository ppa:scott/ppa
  sudo apt-get update
  sudo apt-get upgrade

Check you have dmsetup 2.02.54-1ubuntu4~ppa1

  dpkg-query -W dmsetup

Then reboot.