Index: head/sys/dev/hyperv/include/vmbus.h
===================================================================
--- head/sys/dev/hyperv/include/vmbus.h
+++ head/sys/dev/hyperv/include/vmbus.h
@@ -133,6 +133,7 @@
 		    const struct vmbus_chan_br *cbr, const void *udata,
 		    int udlen, vmbus_chan_callback_t cb, void *cbarg);
 void		vmbus_chan_close(struct vmbus_channel *chan);
+void		vmbus_chan_intr_drain(struct vmbus_channel *chan);
 
 int		vmbus_chan_gpadl_connect(struct vmbus_channel *chan,
 		    bus_addr_t paddr, int size, uint32_t *gpadl);
Index: head/sys/dev/hyperv/vmbus/vmbus_chan.c
===================================================================
--- head/sys/dev/hyperv/vmbus/vmbus_chan.c
+++ head/sys/dev/hyperv/vmbus/vmbus_chan.c
@@ -756,6 +756,13 @@
 	vmbus_chan_close_internal(chan);
 }
 
+void
+vmbus_chan_intr_drain(struct vmbus_channel *chan)
+{
+
+	taskqueue_drain(chan->ch_tq, &chan->ch_task);
+}
+
 int
 vmbus_chan_send(struct vmbus_channel *chan, uint16_t type, uint16_t flags,
     void *data, int dlen, uint64_t xactid)