Patch "macvlan: Fix one possible double free" has been added to the 4.9-stable tree

This is a note to let you know that I've just added the patch titled

macvlan: Fix one possible double free

to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
macvlan-fix-one-possible-double-free.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Gao Feng <[email protected]>
Date: Tue, 26 Dec 2017 21:44:32 +0800
Subject: macvlan: Fix one possible double free

From: Gao Feng <[email protected]>

[ Upstream commit d02fd6e7d2933ede6478a15f9e4ce8a93845824e ]

Because the macvlan_uninit would free the macvlan port, so there is one double free case in macvlan_common_newlink. When the macvlan port is just created, then register_netdevice or netdev_upper_dev_link failed and they would invoke macvlan_uninit. Then it would reach the macvlan_port_destroy which triggers the double free.

---
 drivers/net/macvlan.c |    7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

@@ -1377,9 +1377,14 @@ int macvlan_common_newlink(struct net *s
 	return 0;
 
 unregister_netdev:
+	/* macvlan_uninit would free the macvlan port */
 	unregister_netdevice(dev);
+	return err;
 destroy_macvlan_port:
-	if (create)
+	/* the macvlan port may be freed by macvlan_uninit when fail to register.
+	 * so we destroy the macvlan port only when it's valid.
+	 */
+	if (create && macvlan_port_get_rtnl(dev))
 		macvlan_port_destroy(port->dev);
 	return err;
 }

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/macvlan-fix-one-possible-double-free.patch