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Commit ed148168 authored by Cong Wang's avatar Cong Wang Committed by David S. Miller
Browse files

cls_cgroup: use tcf_exts_get_net() before call_rcu() 



Hold netns refcnt before call_rcu() and release it after
the tcf_exts_destroy() is done.

Note, on ->destroy() path we have to respect the return value
of tcf_exts_get_net(), on other paths it should always return
true, so we don't need to care.

Cc: Lucas Bates <lucasb@mojatatu.com>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: default avatarCong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent aae2c35e

net/sched/cls_cgroup.c

+18 −6
Original line number Diff line number Diff line
@@ -60,15 +60,21 @@ static const struct nla_policy cgroup_policy[TCA_CGROUP_MAX + 1] = { 
	[TCA_CGROUP_EMATCHES]	= { .type = NLA_NESTED },

};



static void __cls_cgroup_destroy(struct cls_cgroup_head *head)

{

	tcf_exts_destroy(&head->exts);

	tcf_em_tree_destroy(&head->ematches);

	tcf_exts_put_net(&head->exts);

	kfree(head);

}



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);

	__cls_cgroup_destroy(head);

	rtnl_unlock();

}
@@ -124,8 +130,10 @@ static int cls_cgroup_change(struct net *net, struct sk_buff *in_skb, 
		goto errout;



	rcu_assign_pointer(tp->root, new);

	if (head)

	if (head) {

		tcf_exts_get_net(&head->exts);

		call_rcu(&head->rcu, cls_cgroup_destroy_rcu);

	}

	return 0;

errout:

	tcf_exts_destroy(&new->exts);
@@ -138,8 +146,12 @@ static void cls_cgroup_destroy(struct tcf_proto *tp) 
	struct cls_cgroup_head *head = rtnl_dereference(tp->root);



	/* Head can still be NULL due to cls_cgroup_init(). */

	if (head)

	if (head) {

		if (tcf_exts_get_net(&head->exts))

			call_rcu(&head->rcu, cls_cgroup_destroy_rcu);

		else

			__cls_cgroup_destroy(head);

	}

}



static int cls_cgroup_delete(struct tcf_proto *tp, void *arg, bool *last)