Comment 15 for bug 879710

I added this corresponding line:

   def unmount_dev(self):
        self.context.cancel_cleanup(self.unmount_dev)
        run_cmd('chroot', '%s' % self.context.chroot_dir, '/etc/init.d/cron','stop') // <-- HERE
        run_cmd('umount', '%s/dev' % self.context.chroot_dir)

That seems to be a temporary workaround for the problem I was seeing (same as @rchilliard -- lsof showed a cron open file to /dev/null).

I also had this working up until several days ago without anything else changing and then it suddenly broke.