--- a/usr/src/lib/install_target/controller.py	Fri May 06 13:42:30 2011 +0100
+++ b/usr/src/lib/install_target/controller.py	Fri May 06 18:34:37 2011 +0100
@@ -590,6 +590,8 @@
                         new_slice = partition.add_slice("0", start,
                             slice_size, Size.sector_units)
                         break
+                else:
+                    return
 
         new_slice.tag = V_ROOT
         new_slice.in_vdev = in_vdev