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

[jj]

I am use libvirt master branch to test LXC , the lastest commit of the master branch is 03d813bbcd7b4a18360105500672b84d985dd889,
by Marek Marczykowski <marmarek at invisiblethingslab.com>
on  Thu May 23 02:01:30 2013 +0200,
 
root at 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 at wheezy:/tmp# virsh -c lxc:/// define test.xml 
Domain vmtest defined from test.xml

root at 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
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