Index: head/sys/netpfil/ipfw/ip_dn_io.c
===================================================================
--- head/sys/netpfil/ipfw/ip_dn_io.c
+++ head/sys/netpfil/ipfw/ip_dn_io.c
@@ -711,8 +711,8 @@
 		dn_drain_queue();
 	}
 
-	DN_BH_WUNLOCK();
 	dn_reschedule();
+	DN_BH_WUNLOCK();
 	if (q.head != NULL)
 		dummynet_send(q.head);
 	CURVNET_RESTORE();
Index: head/sys/netpfil/ipfw/ip_dummynet.c
===================================================================
--- head/sys/netpfil/ipfw/ip_dummynet.c
+++ head/sys/netpfil/ipfw/ip_dummynet.c
@@ -75,6 +75,7 @@
 
 /*---- callout hooks. ----*/
 static struct callout dn_timeout;
+static int dn_gone;
 static struct task	dn_task;
 static struct taskqueue	*dn_tq = NULL;
 
@@ -90,6 +91,8 @@
 dn_reschedule(void)
 {
 
+	if (dn_gone != 0)
+		return;
 	callout_reset_sbt(&dn_timeout, tick_sbt, 0, dummynet, NULL,
 	    C_HARDCLOCK | C_DIRECT_EXEC);
 }
@@ -2179,9 +2182,11 @@
 static void
 ip_dn_destroy(int last)
 {
-	callout_drain(&dn_timeout);
-
 	DN_BH_WLOCK();
+	/* ensure no more callouts are started */
+	dn_gone = 1;
+
+	/* check for last */
 	if (last) {
 		ND("removing last instance\n");
 		ip_dn_ctl_ptr = NULL;
@@ -2190,6 +2195,8 @@
 
 	dummynet_flush();
 	DN_BH_WUNLOCK();
+
+	callout_drain(&dn_timeout);
 	taskqueue_drain(dn_tq, &dn_task);
 	taskqueue_free(dn_tq);
 
Index: head/sys/netpfil/ipfw/ip_fw2.c
===================================================================
--- head/sys/netpfil/ipfw/ip_fw2.c
+++ head/sys/netpfil/ipfw/ip_fw2.c
@@ -2814,11 +2814,10 @@
 
 	IPFW_UH_WLOCK(chain);
 	IPFW_UH_WUNLOCK(chain);
-	IPFW_UH_WLOCK(chain);
 
-	IPFW_WLOCK(chain);
 	ipfw_dyn_uninit(0);	/* run the callout_drain */
-	IPFW_WUNLOCK(chain);
+
+	IPFW_UH_WLOCK(chain);
 
 	reap = NULL;
 	IPFW_WLOCK(chain);