netdev - [PATCH net-next 05/14] net: sched: act_ipt: remove dependency on rtnl lock

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Date:   Mon,  6 Aug 2018 09:54:16 +0300
From:   Vlad Buslov <vladbu@...lanox.com>
To:     netdev@...r.kernel.org
Cc:     davem@...emloft.net, jhs@...atatu.com, xiyou.wangcong@...il.com,
        jiri@...nulli.us, pablo@...filter.org, kadlec@...ckhole.kfki.hu,
        fw@...len.de, ast@...nel.org, daniel@...earbox.net,
        edumazet@...gle.com, keescook@...omium.org,
        marcelo.leitner@...il.com, Vlad Buslov <vladbu@...lanox.com>
Subject: [PATCH net-next 05/14] net: sched: act_ipt: remove dependency on rtnl lock

Use tcf spinlock to protect ipt action private data from concurrent
modification during dump. Ipt init already takes tcf spinlock when
modifying ipt state.

Signed-off-by: Vlad Buslov <vladbu@...lanox.com>
---
 net/sched/act_ipt.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/sched/act_ipt.c b/net/sched/act_ipt.c
index 0dc787a57798..e149f0e66cb6 100644
--- a/net/sched/act_ipt.c
+++ b/net/sched/act_ipt.c
@@ -288,6 +288,7 @@ static int tcf_ipt_dump(struct sk_buff *skb, struct tc_action *a, int bind,
 	 * for foolproof you need to not assume this
 	 */
 
+	spin_lock_bh(&ipt->tcf_lock);
 	t = kmemdup(ipt->tcfi_t, ipt->tcfi_t->u.user.target_size, GFP_ATOMIC);
 	if (unlikely(!t))
 		goto nla_put_failure;
@@ -307,10 +308,12 @@ static int tcf_ipt_dump(struct sk_buff *skb, struct tc_action *a, int bind,
 	if (nla_put_64bit(skb, TCA_IPT_TM, sizeof(tm), &tm, TCA_IPT_PAD))
 		goto nla_put_failure;
 
+	spin_unlock_bh(&ipt->tcf_lock);
 	kfree(t);
 	return skb->len;
 
 nla_put_failure:
+	spin_unlock_bh(&ipt->tcf_lock);
 	nlmsg_trim(skb, b);
 	kfree(t);
 	return -1;
-- 
2.7.5