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Message-ID: <lsq.1465842997.484197915@decadent.org.uk>
Date: Mon, 13 Jun 2016 19:36:37 +0100
From: Ben Hutchings <ben@...adent.org.uk>
To: linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC: akpm@...ux-foundation.org, "Sven Eckelmann" <sven@...fation.org>,
"Antonio Quartulli" <a@...table.cc>,
"Marek Lindner" <mareklindner@...mailbox.ch>
Subject: [PATCH 3.16 061/114] batman-adv: Fix reference counting of vlan
object for tt_local_entry
3.16.36-rc1 review patch. If anyone has any objections, please let me know.
------------------
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>
[bwh: Backported to 3.16:
- s/_put/_free_ref/ in various function names
- Adjust context]
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
net/batman-adv/translation-table.c | 42 ++++----------------------------------
net/batman-adv/types.h | 2 ++
2 files changed, 6 insertions(+), 38 deletions(-)
--- a/net/batman-adv/translation-table.c
+++ b/net/batman-adv/translation-table.c
@@ -176,8 +176,10 @@ 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);
+ }
}
/**
@@ -595,6 +597,7 @@ bool batadv_tt_local_add(struct net_devi
atomic_set(&tt_local->common.refcount, 2);
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
@@ -908,7 +911,6 @@ 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;
uint32_t i;
@@ -944,14 +946,6 @@ int batadv_tt_local_seq_print_text(struc
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,
@@ -969,9 +963,7 @@ 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();
}
@@ -1016,7 +1008,6 @@ uint16_t batadv_tt_local_remove(struct b
{
struct batadv_tt_local_entry *tt_local_entry;
uint16_t 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);
@@ -1056,14 +1047,6 @@ uint16_t batadv_tt_local_remove(struct b
/* 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);
@@ -1136,7 +1119,6 @@ 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;
uint32_t i;
@@ -1158,14 +1140,6 @@ 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);
@@ -3174,7 +3148,6 @@ 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 */
@@ -3204,13 +3177,6 @@ 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
@@ -934,10 +934,12 @@ 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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