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author | Sven Eckelmann <sven@narfation.org> | 2016-03-11 15:44:06 (GMT) |
---|---|---|
committer | Antonio Quartulli <a@unstable.cc> | 2016-04-29 11:46:11 (GMT) |
commit | abe59c65225ccd63a5964e2f2a73dd2995b948e7 (patch) | |
tree | c4d0400fc0300e70782296e1ac8375a98625d2ac | |
parent | a33d970d0b54b09746d5540af8271fad4eb10229 (diff) | |
download | linux-abe59c65225ccd63a5964e2f2a73dd2995b948e7.tar.xz |
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 <sven@narfation.org>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Antonio Quartulli <a@unstable.cc>
-rw-r--r-- | net/batman-adv/originator.c | 16 | ||||
-rw-r--r-- | net/batman-adv/types.h | 2 |
2 files changed, 7 insertions, 11 deletions
diff --git a/net/batman-adv/originator.c b/net/batman-adv/originator.c index d52f67a..c355a82 100644 --- a/net/batman-adv/originator.c +++ b/net/batman-adv/originator.c @@ -250,7 +250,6 @@ static void batadv_neigh_node_release(struct kref *ref) { struct hlist_node *node_tmp; struct batadv_neigh_node *neigh_node; - struct batadv_hardif_neigh_node *hardif_neigh; struct batadv_neigh_ifinfo *neigh_ifinfo; struct batadv_algo_ops *bao; @@ -262,13 +261,7 @@ static void batadv_neigh_node_release(struct kref *ref) batadv_neigh_ifinfo_put(neigh_ifinfo); } - hardif_neigh = batadv_hardif_neigh_get(neigh_node->if_incoming, - neigh_node->addr); - if (hardif_neigh) { - /* batadv_hardif_neigh_get() increases refcount too */ - batadv_hardif_neigh_put(hardif_neigh); - batadv_hardif_neigh_put(hardif_neigh); - } + batadv_hardif_neigh_put(neigh_node->hardif_neigh); if (bao->bat_neigh_free) bao->bat_neigh_free(neigh_node); @@ -665,6 +658,10 @@ batadv_neigh_node_new(struct batadv_orig_node *orig_node, neigh_node->orig_node = orig_node; neigh_node->last_seen = jiffies; + /* increment unique neighbor refcount */ + kref_get(&hardif_neigh->refcount); + neigh_node->hardif_neigh = hardif_neigh; + /* extra reference for return */ kref_init(&neigh_node->refcount); kref_get(&neigh_node->refcount); @@ -673,9 +670,6 @@ batadv_neigh_node_new(struct batadv_orig_node *orig_node, hlist_add_head_rcu(&neigh_node->list, &orig_node->neigh_list); spin_unlock_bh(&orig_node->neigh_list_lock); - /* increment unique neighbor refcount */ - kref_get(&hardif_neigh->refcount); - batadv_dbg(BATADV_DBG_BATMAN, orig_node->bat_priv, "Creating new neighbor %pM for orig_node %pM on interface %s\n", neigh_addr, orig_node->orig, hard_iface->net_dev->name); diff --git a/net/batman-adv/types.h b/net/batman-adv/types.h index 65afd09..1e47fbe 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; }; |