[libvirt] virCommandWait internal error Child process unexpected exit status 1

I am use libvirt master branch to test LXC , the lastest commit of the master branch is 03d813bbcd7b4a18360105500672b84d985dd889, by Marek Marczykowski <marmarek(a)invisiblethingslab.com&gt; on Thu May 23 02:01:30 2013 +0200, root@wheezy:/tmp# cat test.xml <domain type='lxc'> <name>vmtest</name> <memory>500000</memory> <os> <type>exe</type> <cmdline>console=ttyS0</cmdline> <init>/sbin/init</init> </os> <vcpu>1</vcpu> <clock offset='utc'/> <on_poweroff>destroy</on_poweroff> <on_reboot>restart</on_reboot> <on_crash>destroy</on_crash> <devices> <filesystem type="mount"> <source dir="/tmp/x"/> <target dir="/"/> </filesystem> <emulator>/usr/libexec/libvirt_lxc</emulator> <interface type='network'> <source network='default'/> </interface> <console type='pty' /> </devices> </domain> root@wheezy:/tmp# virsh -c lxc:/// define test.xml Domain vmtest defined from test.xml root@wheezy:/tmp# virsh -c lxc:/// start vmtest error: Failed to start domain vmtest error: internal error Child process (PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin LIBVIRT_DEBUG=3 LIBVIRT_LOG_OUTPUTS=3:stderr /usr/libexec/libvirt_lxc --name vmtest --console 19 --security=none --handshake 22 --background --veth veth7) unexpected exit status 1 below's a libvirtd log 2013-05-25 14:46:58.727+0000: 7865: error : virCommandWait:2354 : internal error Child process (PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin LIBVIRT_DEBUG=3 LIBVIRT_LOG_OUTPUTS=3:stderr /usr/libexec/libvirt_lxc --name vmtest --console 19 --security=none --handshake 22 --background --veth veth7) unexpected exit status 1