net_sched: use tcf_queue_work() in cgroup filter
Defer the tcf_exts_destroy() in RCU callback to
tc filter workqueue and get RTNL lock.
Reported-by: Chris Mi <chrism@mellanox.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Jiri Pirko <jiri@resnulli.us>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sched/cls_cgroup.c b/net/sched/cls_cgroup.c
index d48452f..a97e069 100644
--- a/net/sched/cls_cgroup.c
+++ b/net/sched/cls_cgroup.c
@@ -23,7 +23,10 @@ struct cls_cgroup_head {
struct tcf_exts exts;
struct tcf_ematch_tree ematches;
struct tcf_proto *tp;
- struct rcu_head rcu;
+ union {
+ struct work_struct work;
+ struct rcu_head rcu;
+ };
};
static int cls_cgroup_classify(struct sk_buff *skb, const struct tcf_proto *tp,
@@ -57,15 +60,26 @@ static const struct nla_policy cgroup_policy[TCA_CGROUP_MAX + 1] = {
[TCA_CGROUP_EMATCHES] = { .type = NLA_NESTED },
};
+static void cls_cgroup_destroy_work(struct work_struct *work)
+{
+ struct cls_cgroup_head *head = container_of(work,
+ struct cls_cgroup_head,
+ work);
+ rtnl_lock();
+ tcf_exts_destroy(&head->exts);
+ tcf_em_tree_destroy(&head->ematches);
+ kfree(head);
+ rtnl_unlock();
+}
+
static void cls_cgroup_destroy_rcu(struct rcu_head *root)
{
struct cls_cgroup_head *head = container_of(root,
struct cls_cgroup_head,
rcu);
- tcf_exts_destroy(&head->exts);
- tcf_em_tree_destroy(&head->ematches);
- kfree(head);
+ INIT_WORK(&head->work, cls_cgroup_destroy_work);
+ tcf_queue_work(&head->work);
}
static int cls_cgroup_change(struct net *net, struct sk_buff *in_skb,
