diff --git a/tests/sys/kern/sigsys.c b/tests/sys/kern/sigsys.c
index 14cdcd6a836..d135ed77749 100644
--- a/tests/sys/kern/sigsys.c
+++ b/tests/sys/kern/sigsys.c
@@ -63,7 +63,7 @@ sigsys_test(int knob)
 static void
 sysctlset(const char *name, int val)
 {
-	size_t oldlen;
+	size_t oldlen = sizeof(int);
 	int oldval;
 	char buf[80];