From: Sven Eckelmann <s...@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 <s...@narfation.org>
Signed-off-by: Marek Lindner <mareklind...@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
