netdev - [PATCH 2/4] batman-adv: fix neigh reference imbalance

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Message-Id: <1399736110-22333-3-git-send-email-antonio@meshcoding.com>
Date:	Sat, 10 May 2014 17:35:08 +0200
From:	Antonio Quartulli <antonio@...hcoding.com>
To:	davem@...emloft.net
Cc:	netdev@...r.kernel.org, b.a.t.m.a.n@...ts.open-mesh.org,
	Simon Wunderlich <simon@...n-mesh.com>,
	Marek Lindner <mareklindner@...mailbox.ch>,
	Antonio Quartulli <antonio@...hcoding.com>
Subject: [PATCH 2/4] batman-adv: fix neigh reference imbalance

From: Simon Wunderlich <simon@...n-mesh.com>

When an interface is removed from batman-adv, the orig_ifinfo of a
orig_node may be removed without releasing the router first.
This will prevent the reference for the neighbor pointed at by the
orig_ifinfo->router to be released, and this leak may result in
reference leaks for the interface used by this neighbor. Fix that.

This is a regression introduced by
7351a4822d42827ba0110677c0cbad88a3d52585
("batman-adv: split out router from orig_node").

Reported-by: Antonio Quartulli <antonio@...n-mesh.com>
Signed-off-by: Simon Wunderlich <simon@...n-mesh.com>
Signed-off-by: Marek Lindner <mareklindner@...mailbox.ch>
Signed-off-by: Antonio Quartulli <antonio@...hcoding.com>
---
 net/batman-adv/originator.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/net/batman-adv/originator.c b/net/batman-adv/originator.c
index ffd9dfb..a43da69 100644
--- a/net/batman-adv/originator.c
+++ b/net/batman-adv/originator.c
@@ -501,12 +501,17 @@ batadv_neigh_node_get(const struct batadv_orig_node *orig_node,
 static void batadv_orig_ifinfo_free_rcu(struct rcu_head *rcu)
 {
 	struct batadv_orig_ifinfo *orig_ifinfo;
+	struct batadv_neigh_node *router;
 
 	orig_ifinfo = container_of(rcu, struct batadv_orig_ifinfo, rcu);
 
 	if (orig_ifinfo->if_outgoing != BATADV_IF_DEFAULT)
 		batadv_hardif_free_ref_now(orig_ifinfo->if_outgoing);
 
+	/* this is the last reference to this object */
+	router = rcu_dereference_protected(orig_ifinfo->router, true);
+	if (router)
+		batadv_neigh_node_free_ref_now(router);
 	kfree(orig_ifinfo);
 }
 
-- 
1.8.5.5

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