netdev - [PATCH 02/14] netfilter: ipt_CLUSTERIP: put config instead of freeing it

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Message-Id: <20180302203302.3724-3-pablo@netfilter.org>
Date:   Fri,  2 Mar 2018 21:32:50 +0100
From:   Pablo Neira Ayuso <pablo@...filter.org>
To:     netfilter-devel@...r.kernel.org
Cc:     davem@...emloft.net, netdev@...r.kernel.org
Subject: [PATCH 02/14] netfilter: ipt_CLUSTERIP: put config instead of freeing it

From: Florian Westphal <fw@...len.de>

Once struct is added to per-netns list it becomes visible to other cpus,
so we cannot use kfree().

Also delay setting entries refcount to 1 until after everything is
initialised so that when we call clusterip_config_put() in this spot
entries is still zero.

Signed-off-by: Florian Westphal <fw@...len.de>
Signed-off-by: Pablo Neira Ayuso <pablo@...filter.org>
---
 net/ipv4/netfilter/ipt_CLUSTERIP.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/net/ipv4/netfilter/ipt_CLUSTERIP.c b/net/ipv4/netfilter/ipt_CLUSTERIP.c
index 4c8cfd352687..8a8ae61cea71 100644
--- a/net/ipv4/netfilter/ipt_CLUSTERIP.c
+++ b/net/ipv4/netfilter/ipt_CLUSTERIP.c
@@ -232,7 +232,6 @@ clusterip_config_init(struct net *net, const struct ipt_clusterip_tgt_info *i,
 	c->hash_mode = i->hash_mode;
 	c->hash_initval = i->hash_initval;
 	refcount_set(&c->refcount, 1);
-	refcount_set(&c->entries, 1);
 
 	spin_lock_bh(&cn->lock);
 	if (__clusterip_config_find(net, ip)) {
@@ -263,8 +262,10 @@ clusterip_config_init(struct net *net, const struct ipt_clusterip_tgt_info *i,
 
 	c->notifier.notifier_call = clusterip_netdev_event;
 	err = register_netdevice_notifier(&c->notifier);
-	if (!err)
+	if (!err) {
+		refcount_set(&c->entries, 1);
 		return c;
+	}
 
 #ifdef CONFIG_PROC_FS
 	proc_remove(c->pde);
@@ -273,7 +274,7 @@ clusterip_config_init(struct net *net, const struct ipt_clusterip_tgt_info *i,
 	spin_lock_bh(&cn->lock);
 	list_del_rcu(&c->list);
 	spin_unlock_bh(&cn->lock);
-	kfree(c);
+	clusterip_config_put(c);
 
 	return ERR_PTR(err);
 }
-- 
2.11.0