net/sched: act_ct: Fix leak of ct zone template on replace

Currently, on replace, the previous action instance params
is swapped with a newly allocated params. The old params is
only freed (via kfree_rcu), without releasing the allocated
ct zone template related to it.

Call tcf_ct_params_free (via call_rcu) for the old params,
so it will release it.

Fixes: b57dc7c1 ("net/sched: Introduce action ct")
Signed-off-by: Paul Blakey <paulb@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sched/act_ct.c

@@ -739,7 +739,7 @@ static int tcf_ct_init(struct net *net, struct nlattr *nla,
 	if (goto_ch)
 		tcf_chain_put_by_act(goto_ch);
 	if (params)
-		kfree_rcu(params, rcu);
+		call_rcu(&params->rcu, tcf_ct_params_free);
 	if (res == ACT_P_CREATED)
 		tcf_idr_insert(tn, *a);