From: WANG Cong <xiyou.wangcong@gmail.com>
Date: Fri, 13 Feb 2015 21:56:53 +0000 (-0800)
Subject: rtnetlink: call ->dellink on failure when ->newlink exists
X-Git-Tag: v3.2.69~31
X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?p=pandora-kernel.git;a=commitdiff_plain;h=c9f412a4c739cb7eb2b6af845f97539d8d1fcf44;hp=8bcd64423836bad3638684677f6d740bc7c9297f;ds=inline

rtnetlink: call ->dellink on failure when ->newlink exists

[ Upstream commit 7afb8886a05be68e376655539a064ec672de8a8e ]

Ignacy reported that when eth0 is down and add a vlan device
on top of it like:

  ip link add link eth0 name eth0.1 up type vlan id 1

We will get a refcount leak:

  unregister_netdevice: waiting for eth0.1 to become free. Usage count = 2

The problem is when rtnl_configure_link() fails in rtnl_newlink(),
we simply call unregister_device(), but for stacked device like vlan,
we almost do nothing when we unregister the upper device, more work
is done when we unregister the lower device, so call its ->dellink().

Reported-by: Ignacy Gawedzki <ignacy.gawedzki@green-communications.fr>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 2c51dfbed5e6..5b412f0627c3 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -1860,8 +1860,16 @@ replay:
 			goto out;
 
 		err = rtnl_configure_link(dev, ifm);
-		if (err < 0)
-			unregister_netdevice(dev);
+		if (err < 0) {
+			if (ops->newlink) {
+				LIST_HEAD(list_kill);
+
+				ops->dellink(dev, &list_kill);
+				unregister_netdevice_many(&list_kill);
+			} else {
+				unregister_netdevice(dev);
+			}
+		}
 out:
 		put_net(dest_net);
 		return err;