Comment 4 for bug 936756

kernel 3.2.0-30-generic
cgroup-bin 0.37.1-1ubuntu10

After boot cgroup fs is mounted onto /sys/fs/cgroup

# df | grep cgroup
 cgroups 4088656 0 4088656 0% /sys/fs/cgroup
# mount | grep cgroup
cgroups on /sys/fs/cgroup type tmpfs (rw,uid=0,gid=0,mode=0755)
#

and lxc-start complains on "lxc-start: cgroup is not mounted"

To workaround the problem following had to be done:
/etc/init.d/cgconfig stop
mkdir -p /cgroup
mount none -t cgroup /cgroup

After that lxc-start worked properly...