diff --git a/sys/sys/sysctl.h b/sys/sys/sysctl.h
--- a/sys/sys/sysctl.h
+++ b/sys/sys/sysctl.h
@@ -927,6 +927,12 @@
 #define	FEATURE(name, desc)						\
 	SYSCTL_INT_WITH_LABEL(_kern_features, OID_AUTO, name,		\
 	    CTLFLAG_RD | CTLFLAG_CAPRD, SYSCTL_NULL_INT_PTR, 1, desc, "feature")
+/* Same for the dynamic registration. */
+#define	FEATURE_ADD(name, desc)						\
+	sysctl_add_oid(NULL, SYSCTL_CHILDREN(&sysctl___kern_features),	\
+	    OID_AUTO, name,						\
+	    CTLFLAG_RD | CTLFLAG_CAPRD | CTLTYPE_INT | CTLFLAG_MPSAFE,	\
+	    NULL, 1, sysctl_handle_int, "I", desc, "feature");
 
 #endif /* _KERNEL */