--- zzzz-none-000/linux-4.4.60/drivers/misc/lkdtm.c	2017-04-08 07:53:53.000000000 +0000
+++ hawkeye-5590-729/linux-4.4.60/drivers/misc/lkdtm.c	2022-03-30 14:21:52.000000000 +0000
@@ -330,9 +330,10 @@
 static noinline void corrupt_stack(void)
 {
 	/* Use default char array length that triggers stack protection. */
-	char data[8];
-
+	volatile char data[8];
 	memset((void *)data, 0, 64);
+	/* print data so that compiler wouldn't optimize the code */
+	pr_info("print data[0]:%c\n", data[0]);
 }
 
 static void execute_location(void *dst)