systemd requires the directory /sys/fs/cgroup as a mountpoint. It doesn't exist in the kernel (2.6.35). It can't be created with mkdir either because sysfs doesn't allow that. To create the directory this patch from the 2.6.36 kernel must be backported.

http://git.kernel.org/?p=linux/kerne...9dae0071bd11f3

The following kernel config options must be selected.
General setup --->[*] Control Group support
Device Drivers --->
Generic Driver Options --->[*] Maintain a devtmpfs filesystem to mount at /dev[*] Automount devtmpfs at /dev, after the kernel mounted the rootfs (NEW)
File systems --->
< > Kernel automounter support
<*> Kernel automounter version 4 support (also supports v3)