Commit c18bdd01 authored Jan 31, 2016 by Sven Eckelmann Committed by Antonio Quartulli Feb 16, 2016

batman-adv: Only put gw_node list reference when removed

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: bd3524c1 ("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>

parent db92ea5d

net/batman-adv/gateway_client.c

+4 −3

Original line number	Diff line number	Diff line
		@@ -527,10 +527,11 @@ void batadv_gw_node_update(struct batadv_priv *bat_priv,
		* gets dereferenced.
		*/
		spin_lock_bh(&bat_priv->gw.list_lock);
		if (!hlist_unhashed(&gw_node->list)) {
		hlist_del_init_rcu(&gw_node->list);
		spin_unlock_bh(&bat_priv->gw.list_lock);

		batadv_gw_node_free_ref(gw_node);
		}
		spin_unlock_bh(&bat_priv->gw.list_lock);

		curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
		if (gw_node == curr_gw)