From: Vlad Buslov <vladbu@mellanox.com>
Date: Fri, 10 Aug 2018 20:51:45 +0300
Subject: net: sched: act_ipt: remove dependency on rtnl lock
Patch-mainline: v4.19-rc1
Git-commit: ff25276de997f41197ebab91935627c249a30fc4
References: bsc#1109837

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@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 net/sched/act_ipt.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/net/sched/act_ipt.c
+++ b/net/sched/act_ipt.c
@@ -288,6 +288,7 @@ static int tcf_ipt_dump(struct sk_buff *
 	 * 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 *
 	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;