Commit 543e3a8d authored by Bjorn Helgaas's avatar Bjorn Helgaas Committed by David S. Miller
Browse files

netpoll: Fix extra refcount release in netpoll_cleanup()



netpoll_setup() does a dev_hold() on np->dev, the netpoll device.  If it
fails, it correctly does a dev_put() but leaves np->dev set.  If we call
netpoll_cleanup() after the failure, np->dev is still set so we do another
dev_put(), which decrements the refcount an extra time.

It's questionable to call netpoll_cleanup() after netpoll_setup() fails,
but it can be difficult to find the problem, and we can easily avoid it in
this case.  The extra decrements can lead to hangs like this:

  unregister_netdevice: waiting for bond0 to become free. Usage count = -3

Set and clear np->dev at the points where we dev_hold() and dev_put() the
device.

Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 7dd39913
......@@ -603,7 +603,6 @@ int __netpoll_setup(struct netpoll *np, struct net_device *ndev)
const struct net_device_ops *ops;
int err;
np->dev = ndev;
strlcpy(np->dev_name, ndev->name, IFNAMSIZ);
INIT_WORK(&np->cleanup_work, netpoll_async_cleanup);
......@@ -670,6 +669,7 @@ int netpoll_setup(struct netpoll *np)
goto unlock;
}
dev_hold(ndev);
np->dev = ndev;
if (netdev_master_upper_dev_get(ndev)) {
np_err(np, "%s is a slave device, aborting\n", np->dev_name);
......@@ -770,6 +770,7 @@ int netpoll_setup(struct netpoll *np)
return 0;
put:
np->dev = NULL;
dev_put(ndev);
unlock:
rtnl_unlock();
......
Supports Markdown
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment