[PATCH 3.19 009/177] rtnetlink: call ->dellink on failure when ->newlink exists

Greg Kroah-Hartman
2015-03-16T16:00:58Z

From: WANG Cong <xiyou.wangcong@gmail.com>

[ 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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/core/rtnetlink.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)

--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -2124,8 +2124,16 @@ 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;