Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Content-Type: text/plain; charset="UTF-8"
Content-Disposition: inline
Content-Transfer-Encoding: 8bit
MIME-Version: 1.0
From:   Ben Hutchings <ben@decadent.org.uk>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
CC:     akpm@linux-foundation.org, "Sven Eckelmann" <sven@narfation.org>,
        "Simon Wunderlich" <sw@simonwunderlich.de>
Date:   Wed, 28 Feb 2018 15:20:18 +0000
Message-ID: <lsq.1519831218.573581081@decadent.org.uk>
Subject: [PATCH 3.16 052/254] batman-adv: Fix lock for ogm cnt access in
 batadv_iv_ogm_calc_tq
In-Reply-To: <lsq.1519831217.271785318@decadent.org.uk>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

3.16.55-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Sven Eckelmann <sven@narfation.org>

commit 5ba7dcfe77037b67016263ea597a8b431692ecab upstream.

The originator node object orig_neigh_node is used to when accessing the
bcast_own(_sum) and real_packet_count information. The access to them has
to be protected with the spinlock in orig_neigh_node.

But the function uses the lock in orig_node instead. This is incorrect
because they could be two different originator node objects.

Fixes: 0ede9f41b217 ("batman-adv: protect bit operations to count OGMs with spinlock")
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
 net/batman-adv/bat_iv_ogm.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/net/batman-adv/bat_iv_ogm.c
+++ b/net/batman-adv/bat_iv_ogm.c
@@ -1174,7 +1174,7 @@ static int batadv_iv_ogm_calc_tq(struct
 	orig_node->last_seen = jiffies;
 
 	/* find packet count of corresponding one hop neighbor */
-	spin_lock_bh(&orig_node->bat_iv.ogm_cnt_lock);
+	spin_lock_bh(&orig_neigh_node->bat_iv.ogm_cnt_lock);
 	if_num = if_incoming->if_num;
 	orig_eq_count = orig_neigh_node->bat_iv.bcast_own_sum[if_num];
 	neigh_ifinfo = batadv_neigh_ifinfo_new(neigh_node, if_outgoing);
@@ -1184,7 +1184,7 @@ static int batadv_iv_ogm_calc_tq(struct
 	} else {
 		neigh_rq_count = 0;
 	}
-	spin_unlock_bh(&orig_node->bat_iv.ogm_cnt_lock);
+	spin_unlock_bh(&orig_neigh_node->bat_iv.ogm_cnt_lock);
 
 	/* pay attention to not get a value bigger than 100 % */
 	if (orig_eq_count > neigh_rq_count)