The following commit has been merged in the merge/master branch: commit 20ca393adddfe31b47090c0afa4e8aa2ba65ec4b Author: Sven Eckelmann sven@narfation.org Date: Fri Mar 11 16:44:05 2016 +0100

batman-adv: Fix reference counting of vlan object for tt_local_entry

The batadv_tt_local_entry was specific to a batadv_softif_vlan and held an implicit reference to it. But this reference was never stored in form of a pointer in the tt_local_entry itself. Instead batadv_tt_local_remove, batadv_tt_local_table_free and batadv_tt_local_purge_pending_clients depend on a consistent state of bat_priv->softif_vlan_list and that batadv_softif_vlan_get always returns the batadv_softif_vlan object which it has a reference for. But batadv_softif_vlan_get cannot guarantee that because it is working only with rcu_read_lock on this list. It can therefore happen that an vid is in this list twice or that batadv_softif_vlan_get cannot find the batadv_softif_vlan for an vid due to some other list operations taking place at the same time.

Instead add a batadv_softif_vlan pointer directly in batadv_tt_local_entry which will be used for the reference counter decremented on release of batadv_tt_local_entry.

Fixes: 9729d2085c0f ("batman-adv: fix TT VLAN inconsistency on VLAN re-add") Signed-off-by: Sven Eckelmann sven@narfation.org Acked-by: Antonio Quartulli a@unstable.cc Signed-off-by: Marek Lindner mareklindner@neomailbox.ch

diff --git a/net/batman-adv/translation-table.c b/net/batman-adv/translation-table.c index 0b43e86..9b4551a 100644 --- a/net/batman-adv/translation-table.c +++ b/net/batman-adv/translation-table.c @@ -215,6 +215,8 @@ static void batadv_tt_local_entry_release(struct kref *ref) tt_local_entry = container_of(ref, struct batadv_tt_local_entry, common.refcount);

+ batadv_softif_vlan_put(tt_local_entry->vlan); + kfree_rcu(tt_local_entry, common.rcu); }

@@ -673,6 +675,7 @@ bool batadv_tt_local_add(struct net_device *soft_iface, const u8 *addr, kref_get(&tt_local->common.refcount); tt_local->last_seen = jiffies; tt_local->common.added_at = tt_local->last_seen; + tt_local->vlan = vlan;

/* the batman interface mac and multicast addresses should never be * purged @@ -991,7 +994,6 @@ int batadv_tt_local_seq_print_text(struct seq_file *seq, void *offset) struct batadv_tt_common_entry *tt_common_entry; struct batadv_tt_local_entry *tt_local; struct batadv_hard_iface *primary_if; - struct batadv_softif_vlan *vlan; struct hlist_head *head; unsigned short vid; u32 i; @@ -1027,14 +1029,6 @@ int batadv_tt_local_seq_print_text(struct seq_file *seq, void *offset) last_seen_msecs = last_seen_msecs % 1000;

no_purge = tt_common_entry->flags & np_flag; - - vlan = batadv_softif_vlan_get(bat_priv, vid); - if (!vlan) { - seq_printf(seq, "Cannot retrieve VLAN %d\n", - BATADV_PRINT_VID(vid)); - continue; - } - seq_printf(seq, " * %pM %4i [%c%c%c%c%c%c] %3u.%03u (%#.8x)\n", tt_common_entry->addr, @@ -1052,9 +1046,7 @@ int batadv_tt_local_seq_print_text(struct seq_file *seq, void *offset) BATADV_TT_CLIENT_ISOLA) ? 'I' : '.'), no_purge ? 0 : last_seen_secs, no_purge ? 0 : last_seen_msecs, - vlan->tt.crc); - - batadv_softif_vlan_put(vlan); + tt_local->vlan->tt.crc); } rcu_read_unlock(); } @@ -1099,7 +1091,6 @@ u16 batadv_tt_local_remove(struct batadv_priv *bat_priv, const u8 *addr, { struct batadv_tt_local_entry *tt_local_entry; u16 flags, curr_flags = BATADV_NO_FLAGS; - struct batadv_softif_vlan *vlan; void *tt_entry_exists;

tt_local_entry = batadv_tt_local_hash_find(bat_priv, addr, vid); @@ -1139,14 +1130,6 @@ u16 batadv_tt_local_remove(struct batadv_priv *bat_priv, const u8 *addr, /* extra call to free the local tt entry */ batadv_tt_local_entry_put(tt_local_entry);

- /* decrease the reference held for this vlan */ - vlan = batadv_softif_vlan_get(bat_priv, vid); - if (!vlan) - goto out; - - batadv_softif_vlan_put(vlan); - batadv_softif_vlan_put(vlan); - out: if (tt_local_entry) batadv_tt_local_entry_put(tt_local_entry); @@ -1219,7 +1202,6 @@ static void batadv_tt_local_table_free(struct batadv_priv *bat_priv) spinlock_t *list_lock; /* protects write access to the hash lists */ struct batadv_tt_common_entry *tt_common_entry; struct batadv_tt_local_entry *tt_local; - struct batadv_softif_vlan *vlan; struct hlist_node *node_tmp; struct hlist_head *head; u32 i; @@ -1241,14 +1223,6 @@ static void batadv_tt_local_table_free(struct batadv_priv *bat_priv) struct batadv_tt_local_entry, common);

- /* decrease the reference held for this vlan */ - vlan = batadv_softif_vlan_get(bat_priv, - tt_common_entry->vid); - if (vlan) { - batadv_softif_vlan_put(vlan); - batadv_softif_vlan_put(vlan); - } - batadv_tt_local_entry_put(tt_local); } spin_unlock_bh(list_lock); @@ -3309,7 +3283,6 @@ static void batadv_tt_local_purge_pending_clients(struct batadv_priv *bat_priv) struct batadv_hashtable *hash = bat_priv->tt.local_hash; struct batadv_tt_common_entry *tt_common; struct batadv_tt_local_entry *tt_local; - struct batadv_softif_vlan *vlan; struct hlist_node *node_tmp; struct hlist_head *head; spinlock_t *list_lock; /* protects write access to the hash lists */ @@ -3339,13 +3312,6 @@ static void batadv_tt_local_purge_pending_clients(struct batadv_priv *bat_priv) struct batadv_tt_local_entry, common);

- /* decrease the reference held for this vlan */ - vlan = batadv_softif_vlan_get(bat_priv, tt_common->vid); - if (vlan) { - batadv_softif_vlan_put(vlan); - batadv_softif_vlan_put(vlan); - } - batadv_tt_local_entry_put(tt_local); } spin_unlock_bh(list_lock); diff --git a/net/batman-adv/types.h b/net/batman-adv/types.h index 443e9b8..65afd09 100644 --- a/net/batman-adv/types.h +++ b/net/batman-adv/types.h @@ -1073,10 +1073,12 @@ struct batadv_tt_common_entry { * struct batadv_tt_local_entry - translation table local entry data * @common: general translation table data * @last_seen: timestamp used for purging stale tt local entries + * @vlan: soft-interface vlan of the entry */ struct batadv_tt_local_entry { struct batadv_tt_common_entry common; unsigned long last_seen; + struct batadv_softif_vlan *vlan; };

/**