From: Bjorn Helgaas <bhelg...@google.com> Date: Thu, 24 Mar 2016 21:56:21 -0500
> 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: Bjorn Helgaas <bhelg...@google.com> Looks good, applied and queued up for -stable. But you probably do want to look into the stacked device issue Neil pointed out. Thanks!
