diff --git a/sys/kern/kern_xxx.c b/sys/kern/kern_xxx.c
index 66d99edb7da..d6687fae0ca 100644
--- a/sys/kern/kern_xxx.c
+++ b/sys/kern/kern_xxx.c
@@ -318,7 +318,8 @@ freebsd4_uname(struct thread *td, struct freebsd4_uname_args *uap)
 {
 	int name[2], error;
 	size_t len;
-	char *s, *us;
+	const char *s;
+	char *us;
 
 	name[0] = CTL_KERN;
 	name[1] = KERN_OSTYPE;