diff --git a/test/signal_demo.cpp b/test/signal_demo.cpp
index c7a2db2..dc7decc 100644
--- a/test/signal_demo.cpp
+++ b/test/signal_demo.cpp
@@ -12,7 +12,7 @@
 #include <unistd.h>
 
 void trace() {
-    *(char*)0 = 2;
+    *(volatile char*)0 = 2;
 }
 
 void bar() {