aboutsummaryrefslogtreecommitdiffstats
path: root/net/batman-adv/bat_iv_ogm.c
diff options
context:
space:
mode:
authorAntonio Quartulli <antonio@open-mesh.com>2014-01-29 11:25:12 +0100
committerAntonio Quartulli <antonio@meshcoding.com>2014-02-17 17:17:01 +0100
commit08bf0ed29c7ded45c477d08618220dd200c3524a (patch)
tree102dc9b539fb06435727c592c720d17fc62ddbb9 /net/batman-adv/bat_iv_ogm.c
parentf1791425cf0bcda43ab9a9a37df1ad3ccb1f6654 (diff)
batman-adv: avoid potential race condition when adding a new neighbour
When adding a new neighbour it is important to atomically perform the following: - check if the neighbour already exists - append the neighbour to the proper list If the two operations are not performed in an atomic context it is possible that two concurrent insertions add the same neighbour twice. Signed-off-by: Antonio Quartulli <antonio@open-mesh.com> Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Diffstat (limited to 'net/batman-adv/bat_iv_ogm.c')
-rw-r--r--net/batman-adv/bat_iv_ogm.c22
1 files changed, 16 insertions, 6 deletions
diff --git a/net/batman-adv/bat_iv_ogm.c b/net/batman-adv/bat_iv_ogm.c
index 512159bf607f..094ae7ca50a0 100644
--- a/net/batman-adv/bat_iv_ogm.c
+++ b/net/batman-adv/bat_iv_ogm.c
@@ -266,7 +266,7 @@ batadv_iv_ogm_neigh_new(struct batadv_hard_iface *hard_iface,
struct batadv_orig_node *orig_neigh)
{
struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
- struct batadv_neigh_node *neigh_node;
+ struct batadv_neigh_node *neigh_node, *tmp_neigh_node;
neigh_node = batadv_neigh_node_new(hard_iface, neigh_addr, orig_node);
if (!neigh_node)
@@ -281,14 +281,24 @@ batadv_iv_ogm_neigh_new(struct batadv_hard_iface *hard_iface,
neigh_node->orig_node = orig_neigh;
neigh_node->if_incoming = hard_iface;
- batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
- "Creating new neighbor %pM for orig_node %pM on interface %s\n",
- neigh_addr, orig_node->orig, hard_iface->net_dev->name);
-
spin_lock_bh(&orig_node->neigh_list_lock);
- hlist_add_head_rcu(&neigh_node->list, &orig_node->neigh_list);
+ tmp_neigh_node = batadv_neigh_node_get(orig_node, hard_iface,
+ neigh_addr);
+ if (!tmp_neigh_node) {
+ hlist_add_head_rcu(&neigh_node->list, &orig_node->neigh_list);
+ } else {
+ kfree(neigh_node);
+ batadv_hardif_free_ref(hard_iface);
+ neigh_node = tmp_neigh_node;
+ }
spin_unlock_bh(&orig_node->neigh_list_lock);
+ if (!tmp_neigh_node)
+ batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
+ "Creating new neighbor %pM for orig_node %pM on interface %s\n",
+ neigh_addr, orig_node->orig,
+ hard_iface->net_dev->name);
+
out:
return neigh_node;
}

Privacy Policy