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Date: Thu, 19 Mar 2020 13:59:51 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Sven Eckelmann <sven@...fation.org>,
Antonio Quartulli <a@...table.cc>,
Marek Lindner <mareklindner@...mailbox.ch>
Subject: [PATCH 4.4 47/93] batman-adv: Fix reference counting of vlan object for tt_local_entry
From: Sven Eckelmann <sven@...fation.org>
commit a33d970d0b54b09746d5540af8271fad4eb10229 upstream.
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: 35df3b298fc8 ("batman-adv: fix TT VLAN inconsistency on VLAN re-add")
Signed-off-by: Sven Eckelmann <sven@...fation.org>
Acked-by: Antonio Quartulli <a@...table.cc>
Signed-off-by: Marek Lindner <mareklindner@...mailbox.ch>
Signed-off-by: Antonio Quartulli <a@...table.cc>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
net/batman-adv/translation-table.c | 44 ++++---------------------------------
net/batman-adv/types.h | 2 +
2 files changed, 7 insertions(+), 39 deletions(-)
--- a/net/batman-adv/translation-table.c
+++ b/net/batman-adv/translation-table.c
@@ -197,8 +197,11 @@ batadv_tt_global_hash_find(struct batadv
static void
batadv_tt_local_entry_free_ref(struct batadv_tt_local_entry *tt_local_entry)
{
- if (atomic_dec_and_test(&tt_local_entry->common.refcount))
+ if (atomic_dec_and_test(&tt_local_entry->common.refcount)) {
+ batadv_softif_vlan_free_ref(tt_local_entry->vlan);
+
kfree_rcu(tt_local_entry, common.rcu);
+ }
}
/**
@@ -638,7 +641,6 @@ bool batadv_tt_local_add(struct net_devi
if (unlikely(hash_added != 0)) {
/* remove the reference for the hash */
batadv_tt_local_entry_free_ref(tt_local);
- batadv_softif_vlan_free_ref(vlan);
goto out;
}
@@ -942,7 +944,6 @@ int batadv_tt_local_seq_print_text(struc
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;
@@ -979,13 +980,6 @@ int batadv_tt_local_seq_print_text(struc
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,
@@ -1003,9 +997,7 @@ int batadv_tt_local_seq_print_text(struc
BATADV_TT_CLIENT_ISOLA) ? 'I' : '.'),
no_purge ? 0 : last_seen_secs,
no_purge ? 0 : last_seen_msecs,
- vlan->tt.crc);
-
- batadv_softif_vlan_free_ref(vlan);
+ tt_local->vlan->tt.crc);
}
rcu_read_unlock();
}
@@ -1050,7 +1042,6 @@ u16 batadv_tt_local_remove(struct batadv
{
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);
@@ -1090,14 +1081,6 @@ u16 batadv_tt_local_remove(struct batadv
/* extra call to free the local tt entry */
batadv_tt_local_entry_free_ref(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_free_ref(vlan);
- batadv_softif_vlan_free_ref(vlan);
-
out:
if (tt_local_entry)
batadv_tt_local_entry_free_ref(tt_local_entry);
@@ -1170,7 +1153,6 @@ static void batadv_tt_local_table_free(s
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;
@@ -1192,14 +1174,6 @@ static void batadv_tt_local_table_free(s
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_free_ref(vlan);
- batadv_softif_vlan_free_ref(vlan);
- }
-
batadv_tt_local_entry_free_ref(tt_local);
}
spin_unlock_bh(list_lock);
@@ -3229,7 +3203,6 @@ static void batadv_tt_local_purge_pendin
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 */
@@ -3259,13 +3232,6 @@ static void batadv_tt_local_purge_pendin
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_free_ref(vlan);
- batadv_softif_vlan_free_ref(vlan);
- }
-
batadv_tt_local_entry_free_ref(tt_local);
}
spin_unlock_bh(list_lock);
--- a/net/batman-adv/types.h
+++ b/net/batman-adv/types.h
@@ -947,10 +947,12 @@ 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;
};
/**
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