diff --git a/include/linux/mm.h b/include/linux/mm.h
index 2e7ec3ee34cf6e69bbf7ab3e6ff4f24b8cc946bf..1983e08f590624cdc9b87e5d1ce149372f3be2f4 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1067,6 +1067,7 @@ vm_fault_t finish_mkwrite_fault(struct vm_fault *vmf);
 
 static inline enum zone_type page_zonenum(const struct page *page)
 {
+	ASSERT_EXCLUSIVE_BITS(page->flags, ZONES_MASK << ZONES_PGSHIFT);
 	return (page->flags >> ZONES_PGSHIFT) & ZONES_MASK;
 }