diff --git a/sys/net/if.c b/sys/net/if.c
--- a/sys/net/if.c
+++ b/sys/net/if.c
@@ -2183,6 +2183,14 @@
 	if (ifp->if_link_state == link_state)
 		return;
 
+	/*
+	 * if_detach_internal() drains the taskqueue_swi from the
+	 * events from this ifnet. Maintain the invariant by
+	 * refusing any changes after the interface was unlinked.
+	 */
+	if (ifp->if_flags & IFF_DYING)
+		return;
+
 	ifp->if_link_state = link_state;
 
 	/* XXXGL: reference ifp? */