From: WANG Cong <[email protected]>

3.12-stable review patch.  If anyone has any objections, please let me know.

===============

[ 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 <[email protected]>
Signed-off-by: Cong Wang <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
Signed-off-by: Jiri Slaby <[email protected]>
---
 net/core/rtnetlink.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index d211eddb9a02..76cc27f3f991 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -1924,8 +1924,16 @@ replay:
                }
 
                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;
-- 
2.3.0

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