Fix segfault on non-numa enabled systems

If a system doesn't support numa, we have an emtpty top level of the balancing
tree (and we get a null dir pointer in build_numa_nodes to boot).  Fix this by
checking for that null condition and adding the unspecified numa node to the
list of all numa nodes.

See https://bugzilla.redhat.com/show_bug.cgi?id=746159 for details

Signed-off-by: Neil Horman <nhorman@tuxdriver.com>

numa.c

@@ -84,6 +84,14 @@ void build_numa_node_list(void)
 	DIR *dir = opendir(SYSFS_NODE_PATH);
 	struct dirent *entry;
 
+	/*
+	 * Add the unspecified node
+	 */
+	numa_nodes = g_list_append(numa_nodes, &unspecified_node);
+
+	if (!dir)
+		return;
+
 	do {
 		entry = readdir(dir);
 		if (!entry)
@@ -96,6 +104,9 @@ void build_numa_node_list(void)
 
 static void free_numa_node(gpointer data)
 {
+	if (data == (void *)(&unspecified_node))
+		return;
+
 	free(data);
 }
 

placement.c

@@ -45,6 +45,12 @@ static void find_best_object(struct topo_obj *d, void *data)
 	uint64_t newload;
 	cpumask_t subset;
 
+	/*
+ 	 * Don't consider the unspecified numa node here
+ 	 */
+	if ((d->obj_type == OBJ_TYPE_NODE) && (d->number == -1))
+		return;
+
 	/*
  	 * If the hint policy is subset, then we only want 
  	 * to consider objects that are within the irqs hint, but