diff --git a/Makefile b/Makefile
index 734722bda17360..f133c9f927e1fa 100644
--- a/Makefile
+++ b/Makefile
@@ -143,7 +143,8 @@ $(filter-out _all sub-make $(CURDIR)/Makefile, $(MAKECMDGOALS)) _all: sub-make
 
 # Invoke a second make in the output directory, passing relevant variables
 sub-make:
-	$(Q)$(MAKE) -C $(KBUILD_OUTPUT) KBUILD_SRC=$(CURDIR) \
+	$(Q)$(MAKE) -C $(KBUILD_OUTPUT) \
+	KBUILD_SRC=$(shell realpath --relative-to=$(KBUILD_OUTPUT) $(CURDIR)) \
 	-f $(CURDIR)/Makefile $(filter-out _all sub-make,$(MAKECMDGOALS))
 
 # Leave processing to above invocation of make
diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c
index d80343429de5f2..bc0363e2bdb1a7 100644
--- a/drivers/net/xen-netfront.c
+++ b/drivers/net/xen-netfront.c
@@ -1818,7 +1818,7 @@ static int talk_to_netback(struct xenbus_device *dev,
 	err = xen_net_read_mac(dev, info->netdev->dev_addr);
 	if (err) {
 		xenbus_dev_fatal(dev, err, "parsing %s/mac", dev->nodename);
-		goto out;
+		goto out_unlocked;
 	}
 
 	rtnl_lock();
@@ -1933,6 +1933,7 @@ static int talk_to_netback(struct xenbus_device *dev,
 	xennet_destroy_queues(info);
  out:
 	rtnl_unlock();
+out_unlocked:
 	device_unregister(&dev->dev);
 	return err;
 }
@@ -1958,10 +1959,6 @@ static int xennet_connect(struct net_device *dev)
 	/* talk_to_netback() sets the correct number of queues */
 	num_queues = dev->real_num_tx_queues;
 
-	rtnl_lock();
-	netdev_update_features(dev);
-	rtnl_unlock();
-
 	if (dev->reg_state == NETREG_UNINITIALIZED) {
 		err = register_netdev(dev);
 		if (err) {
@@ -1971,6 +1968,10 @@ static int xennet_connect(struct net_device *dev)
 		}
 	}
 
+	rtnl_lock();
+	netdev_update_features(dev);
+	rtnl_unlock();
+
 	/*
 	 * All public and private state should now be sane.  Get
 	 * ready to start sending and receiving packets and give the driver
diff --git a/tools/lib/subcmd/Makefile b/tools/lib/subcmd/Makefile
index 95563b8e1ad743..307652c42a7b6e 100644
--- a/tools/lib/subcmd/Makefile
+++ b/tools/lib/subcmd/Makefile
@@ -33,6 +33,9 @@ ifneq ($(WERROR),0)
   CFLAGS += -Werror
 endif
 
+# Don't fail on fallthrough with newer GCCs.
+CFLAGS += -Wno-error=implicit-fallthrough
+
 CFLAGS += -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -D_GNU_SOURCE
 
 CFLAGS += -I$(srctree)/tools/include/