diff --git a/drivers/base/node.c b/drivers/base/node.c
index 31df474d..cc910ad 100644
--- a/drivers/base/node.c
+++ b/drivers/base/node.c
@@ -390,8 +390,14 @@ int register_mem_sect_under_node(struct memory_block *mem_blk, int nid)
 	sect_end_pfn = section_nr_to_pfn(mem_blk->end_section_nr);
 	sect_end_pfn += PAGES_PER_SECTION - 1;
 	for (pfn = sect_start_pfn; pfn <= sect_end_pfn; pfn++) {
-		int page_nid;
+		int page_nid, scn_nr;
 
+		scn_nr = pfn_to_section_nr(pfn);
+		if (!present_section_nr(scn_nr)) {
+			pfn = round_down(pfn + PAGES_PER_SECTION,
+					 PAGES_PER_SECTION) - 1;
+			continue;
+		}
 		page_nid = get_nid_for_pfn(pfn);
 		if (page_nid < 0)
 			continue;
@@ -426,10 +432,18 @@ int unregister_mem_sect_under_nodes(struct memory_block *mem_blk,
 		return -ENOMEM;
 	nodes_clear(*unlinked_nodes);
 
-	sect_start_pfn = section_nr_to_pfn(phys_index);
-	sect_end_pfn = sect_start_pfn + PAGES_PER_SECTION - 1;
+	sect_start_pfn = section_nr_to_pfn(mem_blk->start_section_nr);
+	sect_end_pfn = section_nr_to_pfn(mem_blk->end_section_nr);
+	sect_end_pfn += PAGES_PER_SECTION - 1;
 	for (pfn = sect_start_pfn; pfn <= sect_end_pfn; pfn++) {
-		int nid;
+		int nid, scn_nr;
+
+		scn_nr = pfn_to_section_nr(pfn);
+		if (!present_section_nr(scn_nr)) {
+			pfn = round_down(pfn + PAGES_PER_SECTION,
+					 PAGES_PER_SECTION) - 1;
+			continue;
+		}
 
 		nid = get_nid_for_pfn(pfn);
 		if (nid < 0)