diff --git a/sys/net/sl/if_sl.c b/sys/net/sl/if_sl.c
--- a/sys/net/sl/if_sl.c
+++ b/sys/net/sl/if_sl.c
@@ -470,7 +470,9 @@
 		return (EAFNOSUPPORT);
 	}
 
+	lwkt_gettoken(&sl_token);
 	if (sc->sc_ttyp == NULL || !(ifp->if_flags & IFF_UP)) {
+		lwkt_reltoken(&sl_token);
 		m_freem(m);
 		return (ENETDOWN);
 	}