netdev - [patch net-next 1/2] net/sched: properly assign RCU pointer in tcf_chain_tp

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Message-Id: <20170520130132.1626-1-jiri@resnulli.us>
Date:   Sat, 20 May 2017 15:01:31 +0200
From:   Jiri Pirko <jiri@...nulli.us>
To:     netdev@...r.kernel.org
Cc:     davem@...emloft.net, jhs@...atatu.com, xiyou.wangcong@...il.com,
        edumazet@...gle.com, daniel@...earbox.net,
        simon.horman@...ronome.com, mlxsw@...lanox.com,
        colin.king@...onical.com
Subject: [patch net-next 1/2] net/sched: properly assign RCU pointer in tcf_chain_tp_insert/remove

From: Jiri Pirko <jiri@...lanox.com>

*p_filter_chain is rcu-dereferenced on reader path. So here in writer,
property assign the pointer.

Fixes: 2190d1d0944f ("net: sched: introduce helpers to work with filter chains")
Signed-off-by: Jiri Pirko <jiri@...lanox.com>
---
 net/sched/cls_api.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c
index 4020b8d..85088ed 100644
--- a/net/sched/cls_api.c
+++ b/net/sched/cls_api.c
@@ -351,7 +351,7 @@ static void tcf_chain_tp_insert(struct tcf_chain *chain,
 {
 	if (chain->p_filter_chain &&
 	    *chain_info->pprev == chain->filter_chain)
-		*chain->p_filter_chain = tp;
+		rcu_assign_pointer(*chain->p_filter_chain, tp);
 	RCU_INIT_POINTER(tp->next, tcf_chain_tp_prev(chain_info));
 	rcu_assign_pointer(*chain_info->pprev, tp);
 }
@@ -363,7 +363,7 @@ static void tcf_chain_tp_remove(struct tcf_chain *chain,
 	struct tcf_proto *next = rtnl_dereference(chain_info->next);
 
 	if (chain->p_filter_chain && tp == chain->filter_chain)
-		*chain->p_filter_chain = next;
+		RCU_INIT_POINTER(*chain->p_filter_chain, next);
 	RCU_INIT_POINTER(*chain_info->pprev, next);
 }
 
-- 
2.9.3