diff --git a/sys/cddl/dev/sdt/sdt.c b/sys/cddl/dev/sdt/sdt.c
index cf7b53223cad..3681d722f971 100644
--- a/sys/cddl/dev/sdt/sdt.c
+++ b/sys/cddl/dev/sdt/sdt.c
@@ -169,6 +169,8 @@ sdt_create_probe(struct sdt_probe *probe)
 	 * in the C compiler, so we have to respect const vs non-const.
 	 */
 	strlcpy(func, probe->func, sizeof(func));
+	if (func[0] == '\0')
+		strcpy(func, "none");
 
 	from = probe->name;
 	to = name;