netdev - [PATCH 09/17] batman-adv: Use kref_get for batadv_tvlv_container

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Message-Id: <1462908605-27412-10-git-send-email-a@unstable.cc>
Date:	Wed, 11 May 2016 03:29:57 +0800
From:	Antonio Quartulli <a@...table.cc>
To:	davem@...emloft.net
Cc:	netdev@...r.kernel.org, b.a.t.m.a.n@...ts.open-mesh.org,
	Sven Eckelmann <sven@...fation.org>,
	Marek Lindner <mareklindner@...mailbox.ch>,
	Antonio Quartulli <a@...table.cc>
Subject: [PATCH 09/17] batman-adv: Use kref_get for batadv_tvlv_container_get

From: Sven Eckelmann <sven@...fation.org>

batadv_tvlv_container_get requires that tvlv.container_list_lock is held by
the caller. It is therefore not possible that an item in
tvlv.container_list has an reference counter of 0 and is still in the list

The kref_get function instead WARNs (with debug information) when the
reference counter would still be 0. This makes a bug in batman-adv better
visible because kref_get_unless_zero would have ignored this problem.

Signed-off-by: Sven Eckelmann <sven@...fation.org>
Signed-off-by: Marek Lindner <mareklindner@...mailbox.ch>
Signed-off-by: Antonio Quartulli <a@...table.cc>
---
 net/batman-adv/main.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/net/batman-adv/main.c b/net/batman-adv/main.c
index c8d8bc78a518..5f2974bd1227 100644
--- a/net/batman-adv/main.c
+++ b/net/batman-adv/main.c
@@ -748,9 +748,7 @@ batadv_tvlv_container_get(struct batadv_priv *bat_priv, u8 type, u8 version)
 		if (tvlv_tmp->tvlv_hdr.version != version)
 			continue;
 
-		if (!kref_get_unless_zero(&tvlv_tmp->refcount))
-			continue;
-
+		kref_get(&tvlv_tmp->refcount);
 		tvlv = tvlv_tmp;
 		break;
 	}
-- 
2.8.2