From abe59c65225ccd63a5964e2f2a73dd2995b948e7 Mon Sep 17 00:00:00 2001 From: Sven Eckelmann Date: Fri, 11 Mar 2016 16:44:06 +0100 Subject: batman-adv: Fix reference counting of hardif_neigh_node object for neigh_node The batadv_neigh_node was specific to a batadv_hardif_neigh_node and held an implicit reference to it. But this reference was never stored in form of a pointer in the batadv_neigh_node itself. Instead batadv_neigh_node_release depends on a consistent state of hard_iface->neigh_list and that batadv_hardif_neigh_get always returns the batadv_hardif_neigh_node object which it has a reference for. But batadv_hardif_neigh_get cannot guarantee that because it is working only with rcu_read_lock on this list. It can therefore happen that a neigh_addr is in this list twice or that batadv_hardif_neigh_get cannot find the batadv_hardif_neigh_node for an neigh_addr due to some other list operations taking place at the same time. Instead add a batadv_hardif_neigh_node pointer directly in batadv_neigh_node which will be used for the reference counter decremented on release of batadv_neigh_node. Fixes: cef63419f7db ("batman-adv: add list of unique single hop neighbors per hard-interface") Signed-off-by: Sven Eckelmann Signed-off-by: Marek Lindner Signed-off-by: Antonio Quartulli --- net/batman-adv/types.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'net/batman-adv/types.h') diff --git a/net/batman-adv/types.h b/net/batman-adv/types.h index 65afd090ab3e..1e47fbe8bb7b 100644 --- a/net/batman-adv/types.h +++ b/net/batman-adv/types.h @@ -433,6 +433,7 @@ struct batadv_hardif_neigh_node { * @ifinfo_lock: lock protecting private ifinfo members and list * @if_incoming: pointer to incoming hard-interface * @last_seen: when last packet via this neighbor was received + * @hardif_neigh: hardif_neigh of this neighbor * @refcount: number of contexts the object is used * @rcu: struct used for freeing in an RCU-safe manner */ @@ -444,6 +445,7 @@ struct batadv_neigh_node { spinlock_t ifinfo_lock; /* protects ifinfo_list and its members */ struct batadv_hard_iface *if_incoming; unsigned long last_seen; + struct batadv_hardif_neigh_node *hardif_neigh; struct kref refcount; struct rcu_head rcu; }; -- cgit v1.2.3-59-g8ed1b