[batman-adv] next: batman-adv: Fix reference counting of vlan object for tt_local_entry (20ca393) - commits - lists.open-mesh.org

21 Apr 2016

Repository : ssh://git@open-mesh.org/batman-adv
On branch  : next
...

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
...

20ca393adddfe31b47090c0afa4e8aa2ba65ec4b
 net/batman-adv/translation-table.c | 42 ++++----------------------------------
 net/batman-adv/types.h             |  2 ++
 2 files changed, 6 insertions(+), 38 deletions(-)

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;
 };
/**

    