diff --git a/lib/test_kasan.c b/lib/test_kasan.c
index 502709db41c0..603fd7937b94 100644
--- a/lib/test_kasan.c
+++ b/lib/test_kasan.c
@@ -68,23 +68,30 @@ static void kasan_test_exit(struct kunit *test)
  * normally auto-disabled. When this happens, this test handler reenables
  * tag checking. As tag checking can be only disabled or enabled per CPU, this
  * handler disables migration (preemption).
+ *
+ * Since the compiler doesn't see that the expression can change the fail_data
+ * fields, it can reorder or optimize away the accesses to those fields.
+ * Use READ/WRITE_ONCE() for the accesses and compiler barriers around the
+ * expression to prevent that.
  */
 #define KUNIT_EXPECT_KASAN_FAIL(test, expression) do {		\
 	if (IS_ENABLED(CONFIG_KASAN_HW_TAGS))			\
 		migrate_disable();				\
-	fail_data.report_expected = true;			\
-	fail_data.report_found = false;				\
+	WRITE_ONCE(fail_data.report_expected, true);		\
+	WRITE_ONCE(fail_data.report_found, false);		\
 	kunit_add_named_resource(test,				\
 				NULL,				\
 				NULL,				\
 				&resource,			\
 				"kasan_data", &fail_data);	\
+	barrier();						\
 	expression;						\
+	barrier();						\
 	KUNIT_EXPECT_EQ(test,					\
-			fail_data.report_expected,		\
-			fail_data.report_found);		\
+			READ_ONCE(fail_data.report_expected),	\
+			READ_ONCE(fail_data.report_found));	\
 	if (IS_ENABLED(CONFIG_KASAN_HW_TAGS)) {			\
-		if (fail_data.report_found)			\
+		if (READ_ONCE(fail_data.report_found))		\
 			kasan_enable_tagging();			\
 		migrate_enable();				\
 	}							\
diff --git a/mm/kasan/report.c b/mm/kasan/report.c
index e93d7973792e..234f35a84f19 100644
--- a/mm/kasan/report.c
+++ b/mm/kasan/report.c
@@ -331,7 +331,7 @@ static void kasan_update_kunit_status(struct kunit *cur_test)
 	}
 
 	kasan_data = (struct kunit_kasan_expectation *)resource->data;
-	kasan_data->report_found = true;
+	WRITE_ONCE(kasan_data->report_found, true);
 	kunit_put_resource(resource);
 }
 #endif /* IS_ENABLED(CONFIG_KUNIT) */