diff --git a/lib/test_kasan.c b/lib/test_kasan.c
index 044c54d..c1efb1b 100644
--- a/lib/test_kasan.c
+++ b/lib/test_kasan.c
@@ -114,7 +114,7 @@
 		kfree(ptr1);
 		return;
 	}
-	ptr2[size1] = 'x';
+	ptr2[size2] = 'x';
 	kfree(ptr2);
 }