batadv_gw_select requires that the caller already has a valid reference for new_gw_node. It is therefore not possible that it has an reference counter of 0 and was still given to this function
The kref_get function instead WARNs (with debug information) when the reference counter would still be 0. This makes a bug in batman-adv better visible because kref_get_unless_zero would have ignored this problem.
Signed-off-by: Sven Eckelmann sven@narfation.org --- net/batman-adv/gateway_client.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/net/batman-adv/gateway_client.c b/net/batman-adv/gateway_client.c index c59aff5..bb1c4f3 100644 --- a/net/batman-adv/gateway_client.c +++ b/net/batman-adv/gateway_client.c @@ -135,8 +135,8 @@ static void batadv_gw_select(struct batadv_priv *bat_priv,
spin_lock_bh(&bat_priv->gw.list_lock);
- if (new_gw_node && !kref_get_unless_zero(&new_gw_node->refcount)) - new_gw_node = NULL; + if (new_gw_node) + kref_get(&new_gw_node->refcount);
curr_gw_node = rcu_dereference_protected(bat_priv->gw.curr_gw, 1); rcu_assign_pointer(bat_priv->gw.curr_gw, new_gw_node);