diff options
| author | Sven Eckelmann <sven@narfation.org> | 2020-03-18 00:26:48 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-03-20 09:06:24 +0100 |
| commit | 114cdd5635ac6dd9c0e122714993727aacc9407e (patch) | |
| tree | adacea138d2173303762e1aed2fe0535ca6325a9 | |
| parent | 48aafec676bbff195d6f31bafca08809485d3f28 (diff) | |
batman-adv: Only put gw_node list reference when removed
commit c18bdd018e8912ca73ad6c12120b7283b5038875 upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | net/batman-adv/gateway_client.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/net/batman-adv/gateway_client.c b/net/batman-adv/gateway_client.c index 6abfba1e227f..055baa396260 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); |