Index: head/sys/dev/hyperv/vmbus/hv_channel.c
===================================================================
--- head/sys/dev/hyperv/vmbus/hv_channel.c
+++ head/sys/dev/hyperv/vmbus/hv_channel.c
@@ -270,12 +270,12 @@
 	if (user_data_len)
 		memcpy(open_msg->user_data, user_data, user_data_len);
 
-	mtx_lock_spin(&hv_vmbus_g_connection.channel_msg_lock);
+	mtx_lock(&hv_vmbus_g_connection.channel_msg_lock);
 	TAILQ_INSERT_TAIL(
 		&hv_vmbus_g_connection.channel_msg_anchor,
 		open_info,
 		msg_list_entry);
-	mtx_unlock_spin(&hv_vmbus_g_connection.channel_msg_lock);
+	mtx_unlock(&hv_vmbus_g_connection.channel_msg_lock);
 
 	ret = hv_vmbus_post_message(
 		open_msg, sizeof(hv_vmbus_channel_open_channel));
@@ -302,12 +302,12 @@
 	}
 
 	cleanup:
-	mtx_lock_spin(&hv_vmbus_g_connection.channel_msg_lock);
+	mtx_lock(&hv_vmbus_g_connection.channel_msg_lock);
 	TAILQ_REMOVE(
 		&hv_vmbus_g_connection.channel_msg_anchor,
 		open_info,
 		msg_list_entry);
-	mtx_unlock_spin(&hv_vmbus_g_connection.channel_msg_lock);
+	mtx_unlock(&hv_vmbus_g_connection.channel_msg_lock);
 	sema_destroy(&open_info->wait_sema);
 	free(open_info, M_DEVBUF);
 
@@ -496,13 +496,13 @@
 	gpadl_msg->child_rel_id = channel->offer_msg.child_rel_id;
 	gpadl_msg->gpadl = next_gpadl_handle;
 
-	mtx_lock_spin(&hv_vmbus_g_connection.channel_msg_lock);
+	mtx_lock(&hv_vmbus_g_connection.channel_msg_lock);
 	TAILQ_INSERT_TAIL(
 		&hv_vmbus_g_connection.channel_msg_anchor,
 		msg_info,
 		msg_list_entry);
 
-	mtx_unlock_spin(&hv_vmbus_g_connection.channel_msg_lock);
+	mtx_unlock(&hv_vmbus_g_connection.channel_msg_lock);
 
 	ret = hv_vmbus_post_message(
 		gpadl_msg,
@@ -541,10 +541,10 @@
 
 cleanup:
 
-	mtx_lock_spin(&hv_vmbus_g_connection.channel_msg_lock);
+	mtx_lock(&hv_vmbus_g_connection.channel_msg_lock);
 	TAILQ_REMOVE(&hv_vmbus_g_connection.channel_msg_anchor,
 		msg_info, msg_list_entry);
-	mtx_unlock_spin(&hv_vmbus_g_connection.channel_msg_lock);
+	mtx_unlock(&hv_vmbus_g_connection.channel_msg_lock);
 
 	sema_destroy(&msg_info->wait_sema);
 	free(msg_info, M_DEVBUF);
@@ -583,10 +583,10 @@
 	msg->child_rel_id = channel->offer_msg.child_rel_id;
 	msg->gpadl = gpadl_handle;
 
-	mtx_lock_spin(&hv_vmbus_g_connection.channel_msg_lock);
+	mtx_lock(&hv_vmbus_g_connection.channel_msg_lock);
 	TAILQ_INSERT_TAIL(&hv_vmbus_g_connection.channel_msg_anchor,
 			info, msg_list_entry);
-	mtx_unlock_spin(&hv_vmbus_g_connection.channel_msg_lock);
+	mtx_unlock(&hv_vmbus_g_connection.channel_msg_lock);
 
 	ret = hv_vmbus_post_message(msg,
 			sizeof(hv_vmbus_channel_gpadl_teardown));
@@ -599,10 +599,10 @@
 	/*
 	 * Received a torndown response
 	 */
-	mtx_lock_spin(&hv_vmbus_g_connection.channel_msg_lock);
+	mtx_lock(&hv_vmbus_g_connection.channel_msg_lock);
 	TAILQ_REMOVE(&hv_vmbus_g_connection.channel_msg_anchor,
 			info, msg_list_entry);
-	mtx_unlock_spin(&hv_vmbus_g_connection.channel_msg_lock);
+	mtx_unlock(&hv_vmbus_g_connection.channel_msg_lock);
 	sema_destroy(&info->wait_sema);
 	free(info, M_DEVBUF);
 
Index: head/sys/dev/hyperv/vmbus/hv_channel_mgmt.c
===================================================================
--- head/sys/dev/hyperv/vmbus/hv_channel_mgmt.c
+++ head/sys/dev/hyperv/vmbus/hv_channel_mgmt.c
@@ -492,7 +492,7 @@
 	/*
 	 * Find the open msg, copy the result and signal/unblock the wait event
 	 */
-	mtx_lock_spin(&hv_vmbus_g_connection.channel_msg_lock);
+	mtx_lock(&hv_vmbus_g_connection.channel_msg_lock);
 
 	TAILQ_FOREACH(msg_info, &hv_vmbus_g_connection.channel_msg_anchor,
 	    msg_list_entry) {
@@ -510,7 +510,7 @@
 		}
 	    }
 	}
-	mtx_unlock_spin(&hv_vmbus_g_connection.channel_msg_lock);
+	mtx_unlock(&hv_vmbus_g_connection.channel_msg_lock);
 
 }
 
@@ -534,7 +534,7 @@
 	/* Find the establish msg, copy the result and signal/unblock
 	 * the wait event
 	 */
-	mtx_lock_spin(&hv_vmbus_g_connection.channel_msg_lock);
+	mtx_lock(&hv_vmbus_g_connection.channel_msg_lock);
 	TAILQ_FOREACH(msg_info, &hv_vmbus_g_connection.channel_msg_anchor,
 		msg_list_entry) {
 	    request_header = (hv_vmbus_channel_msg_header*) msg_info->msg;
@@ -553,7 +553,7 @@
 		}
 	    }
 	}
-	mtx_unlock_spin(&hv_vmbus_g_connection.channel_msg_lock);
+	mtx_unlock(&hv_vmbus_g_connection.channel_msg_lock);
 }
 
 /**
@@ -578,7 +578,7 @@
 	 * wait event.
 	 */
 
-	mtx_lock_spin(&hv_vmbus_g_connection.channel_msg_lock);
+	mtx_lock(&hv_vmbus_g_connection.channel_msg_lock);
 
 	TAILQ_FOREACH(msg_info, &hv_vmbus_g_connection.channel_msg_anchor,
 		msg_list_entry) {
@@ -598,7 +598,7 @@
 		}
 	    }
 	}
-    mtx_unlock_spin(&hv_vmbus_g_connection.channel_msg_lock);
+    mtx_unlock(&hv_vmbus_g_connection.channel_msg_lock);
 }
 
 /**
@@ -618,7 +618,7 @@
 
 	versionResponse = (hv_vmbus_channel_version_response*)hdr;
 
-	mtx_lock_spin(&hv_vmbus_g_connection.channel_msg_lock);
+	mtx_lock(&hv_vmbus_g_connection.channel_msg_lock);
 	TAILQ_FOREACH(msg_info, &hv_vmbus_g_connection.channel_msg_anchor,
 	    msg_list_entry) {
 	    requestHeader = (hv_vmbus_channel_msg_header*) msg_info->msg;
@@ -632,7 +632,7 @@
 		sema_post(&msg_info->wait_sema);
 	    }
 	}
-    mtx_unlock_spin(&hv_vmbus_g_connection.channel_msg_lock);
+    mtx_unlock(&hv_vmbus_g_connection.channel_msg_lock);
 
 }
 
Index: head/sys/dev/hyperv/vmbus/hv_connection.c
===================================================================
--- head/sys/dev/hyperv/vmbus/hv_connection.c
+++ head/sys/dev/hyperv/vmbus/hv_connection.c
@@ -96,26 +96,26 @@
 	 * Add to list before we send the request since we may receive the
 	 * response before returning from this routine
 	 */
-	mtx_lock_spin(&hv_vmbus_g_connection.channel_msg_lock);
+	mtx_lock(&hv_vmbus_g_connection.channel_msg_lock);
 
 	TAILQ_INSERT_TAIL(
 		&hv_vmbus_g_connection.channel_msg_anchor,
 		msg_info,
 		msg_list_entry);
 
-	mtx_unlock_spin(&hv_vmbus_g_connection.channel_msg_lock);
+	mtx_unlock(&hv_vmbus_g_connection.channel_msg_lock);
 
 	ret = hv_vmbus_post_message(
 		msg,
 		sizeof(hv_vmbus_channel_initiate_contact));
 
 	if (ret != 0) {
-		mtx_lock_spin(&hv_vmbus_g_connection.channel_msg_lock);
+		mtx_lock(&hv_vmbus_g_connection.channel_msg_lock);
 		TAILQ_REMOVE(
 			&hv_vmbus_g_connection.channel_msg_anchor,
 			msg_info,
 			msg_list_entry);
-		mtx_unlock_spin(&hv_vmbus_g_connection.channel_msg_lock);
+		mtx_unlock(&hv_vmbus_g_connection.channel_msg_lock);
 		return (ret);
 	}
 
@@ -124,12 +124,12 @@
 	 */
 	ret = sema_timedwait(&msg_info->wait_sema, 5 * hz); /* KYS 5 seconds */
 
-	mtx_lock_spin(&hv_vmbus_g_connection.channel_msg_lock);
+	mtx_lock(&hv_vmbus_g_connection.channel_msg_lock);
 	TAILQ_REMOVE(
 		&hv_vmbus_g_connection.channel_msg_anchor,
 		msg_info,
 		msg_list_entry);
-	mtx_unlock_spin(&hv_vmbus_g_connection.channel_msg_lock);
+	mtx_unlock(&hv_vmbus_g_connection.channel_msg_lock);
 
 	/**
 	 * Check if successful
@@ -166,7 +166,7 @@
 
 	TAILQ_INIT(&hv_vmbus_g_connection.channel_msg_anchor);
 	mtx_init(&hv_vmbus_g_connection.channel_msg_lock, "vmbus channel msg",
-		NULL, MTX_SPIN);
+		NULL, MTX_DEF);
 
 	TAILQ_INIT(&hv_vmbus_g_connection.channel_anchor);
 	mtx_init(&hv_vmbus_g_connection.channel_lock, "vmbus channel",