batadv_gw_node_add requires that the caller already has a valid reference for orig_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 | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-)
diff --git a/net/batman-adv/gateway_client.c b/net/batman-adv/gateway_client.c index bb1c4f3..5839c56 100644 --- a/net/batman-adv/gateway_client.c +++ b/net/batman-adv/gateway_client.c @@ -440,15 +440,11 @@ static void batadv_gw_node_add(struct batadv_priv *bat_priv, if (gateway->bandwidth_down == 0) return;
- if (!kref_get_unless_zero(&orig_node->refcount)) - return; - gw_node = kzalloc(sizeof(*gw_node), GFP_ATOMIC); - if (!gw_node) { - batadv_orig_node_put(orig_node); + if (!gw_node) return; - }
+ kref_get(&orig_node->refcount); INIT_HLIST_NODE(&gw_node->list); gw_node->orig_node = orig_node; gw_node->bandwidth_down = ntohl(gateway->bandwidth_down);