diff --git a/tools/test/stress2/lib/resources.c b/tools/test/stress2/lib/resources.c
index 935a085a58d..1888d1fba87 100644
--- a/tools/test/stress2/lib/resources.c
+++ b/tools/test/stress2/lib/resources.c
@@ -149,7 +149,7 @@ usermem(void)
 }
 
 static void
-cleanupdf()
+cleanupdf(void)
 {
 	unlink(dfpath);
 }