From: Robert Shearman <rshea...@brocade.com>
Date: Sat, 21 Jan 2017 00:21:26 +0000
> @@ -115,8 +115,12 @@ int lwtunnel_build_state(struct net_device *dev, u16
> encap_type,
> ret = -EOPNOTSUPP;
> rcu_read_lock();
Here 'ret' equals -EOPNOTSUPP
> ops = rcu_dereference(lwtun_encaps[encap_type]);
> - if (likely(ops && ops->build_state))
> - ret = ops->build_state(dev, encap, family, cfg, lws);
> + if (likely(ops)) {
> + if (likely(try_module_get(ops->owner) && ops->build_state))
> + ret = ops->build_state(dev, encap, family, cfg, lws);
> + if (ret)
> + module_put(ops->owner);
If try_module_get() fails, 'ret' will still be -EOPNOTSUPP and we will
module_put() on a module we did not grab a reference to.
I think you need to adjust the logic here. You only want to 'put' if
try_module_get() succeeds and ->build_state() returns an error.
