Index: sys/net/if.c
===================================================================
--- sys/net/if.c
+++ sys/net/if.c
@@ -1129,6 +1129,17 @@
 	curvnet->vnet_ifcnt--;
 #endif
 	epoch_wait_preempt(net_epoch_preempt);
+
+	/*
+	 * XXX EPOCH callbacks are run by the system timer.
+	 * Wait 4 ticks to ensure all pending callbacks have
+	 * been executed. This fixes issues about late
+	 * destruction of multicast options which will
+	 * cause leave group calls, which in turn access
+	 * the belonging ifnet structure.
+	 */
+	pause("W", 4);
+
 	/*
 	 * In any case (destroy or vmove) detach us from the groups
 	 * and remove/wait for pending events on the taskq.