From: Antonio Quartulli <a@unstable.cc>
To: davem@davemloft.net
Cc: netdev@vger.kernel.org, b.a.t.m.a.n@lists.open-mesh.org,
Antonio Quartulli <a@unstable.cc>,
Marek Lindner <mareklindner@neomailbox.ch>
Subject: [B.A.T.M.A.N.] [PATCH 1/3] batman-adv: Only put gw_node list reference when removed
Date: Tue, 16 Feb 2016 23:01:26 +0800 [thread overview]
Message-ID: <1455634888-29400-2-git-send-email-a@unstable.cc> (raw)
In-Reply-To: <1455634888-29400-1-git-send-email-a@unstable.cc>
From: Sven Eckelmann <sven@narfation.org>
The batadv_gw_node reference counter in batadv_gw_node_update can only be
reduced when the list entry was actually removed. Otherwise the reference
counter may reach zero when batadv_gw_node_update is called from two
different contexts for the same gw_node but only one context is actually
removing the entry from the list.
The release function for this gw_node is not called inside the list_lock
spinlock protected region because the function batadv_gw_node_update still
holds a gw_node reference for the object pointer on the stack. Thus the
actual release function (when required) will be called only at the end of
the function.
Fixes: bd3524c14bd0 ("batman-adv: remove obsolete deleted attribute for gateway node")
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Antonio Quartulli <a@unstable.cc>
---
net/batman-adv/gateway_client.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/net/batman-adv/gateway_client.c b/net/batman-adv/gateway_client.c
index e6c8382c79ba..ccf70bed0d0c 100644
--- a/net/batman-adv/gateway_client.c
+++ b/net/batman-adv/gateway_client.c
@@ -527,11 +527,12 @@ void batadv_gw_node_update(struct batadv_priv *bat_priv,
* gets dereferenced.
*/
spin_lock_bh(&bat_priv->gw.list_lock);
- hlist_del_init_rcu(&gw_node->list);
+ if (!hlist_unhashed(&gw_node->list)) {
+ hlist_del_init_rcu(&gw_node->list);
+ batadv_gw_node_free_ref(gw_node);
+ }
spin_unlock_bh(&bat_priv->gw.list_lock);
- batadv_gw_node_free_ref(gw_node);
-
curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
if (gw_node == curr_gw)
batadv_gw_reselect(bat_priv);
--
2.7.1
next prev parent reply other threads:[~2016-02-16 15:01 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-16 15:01 [B.A.T.M.A.N.] pull request [net]: batman-adv 20160216 Antonio Quartulli
2016-02-16 15:01 ` Antonio Quartulli [this message]
2016-02-16 15:01 ` [B.A.T.M.A.N.] [PATCH 2/3] batman-adv: Only put orig_node_vlan list reference when removed Antonio Quartulli
2016-02-16 15:01 ` [B.A.T.M.A.N.] [PATCH 3/3] batman-adv: Avoid endless loop in bat-on-bat netdevice check Antonio Quartulli
2016-02-17 4:20 ` [B.A.T.M.A.N.] pull request [net]: batman-adv 20160216 Antonio Quartulli
2016-02-19 20:37 ` David Miller
2016-02-20 5:28 ` Antonio Quartulli
2016-02-23 5:07 ` Antonio Quartulli
2016-02-23 5:12 ` David Miller
2016-02-23 5:36 ` David Miller
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