diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index a2e8a6df7baa..4563cf0626a1 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -75,7 +75,11 @@ extern const char * const migratetype_names[MIGRATE_TYPES];
 
 #ifdef CONFIG_CMA
 #  define is_migrate_cma(migratetype) unlikely((migratetype) == MIGRATE_CMA)
-#  define is_migrate_cma_page(_page) (get_pageblock_migratetype(_page) == MIGRATE_CMA)
+#  define is_migrate_cma_page(_page) ({						\
+	int mt = get_pageblock_migratetype(_page);				\
+	bool ret = (mt == MIGRATE_ISOLATE || mt == MIGRATE_CMA) ? true : false;	\
+	ret;									\
+})
 #  define get_cma_migrate_type() MIGRATE_CMA
 #else
 #  define is_migrate_cma(migratetype) false
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 644cf26c38aa..0a9bc8437aa7 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -480,8 +480,12 @@ unsigned long __get_pfnblock_flags_mask(const struct page *page,
 	bitidx = pfn_to_bitidx(page, pfn);
 	word_bitidx = bitidx / BITS_PER_LONG;
 	bitidx &= (BITS_PER_LONG-1);
-
-	word = bitmap[word_bitidx];
+	/*
+	 * This races, without locks, with set_pfnblock_flags_mask(). Ensure
+	 * a consistent read of the memory array, so that results, even though
+	 * racy, are not corrupted.
+	 */
+	word = READ_ONCE(bitmap[word_bitidx]);
 	return (word >> bitidx) & mask;
 }