diff --git a/mm/sparse.c b/mm/sparse.c
index c5e89eb..100040c 100644
--- a/mm/sparse.c
+++ b/mm/sparse.c
@@ -87,11 +87,8 @@
 	unsigned long root_nr;
 	struct mem_section* root;
 
-	for (root_nr = 0;
-	     root_nr < NR_MEM_SECTIONS;
-	     root_nr += SECTIONS_PER_ROOT) {
-		root = __nr_to_section(root_nr);
-
+	for (root_nr = 0; root_nr < NR_SECTION_ROOTS; root_nr++) {
+		root = __nr_to_section(root_nr * SECTIONS_PER_ROOT);
 		if (!root)
 			continue;