It might be possible that 2 threads access the same data in the same
rcu grace period. The first thread calls call_rcu() to decrement the
refcount and free the data while the second thread increases the
refcount to use the data. To avoid this race condition all refcount
operations have to be atomic.
Reported-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
length = sprintf(buff, "%s\n", batman_if->if_status == IF_NOT_IN_USE ?
"none" : batman_if->soft_iface->name);
length = sprintf(buff, "%s\n", batman_if->if_status == IF_NOT_IN_USE ?
"none" : batman_if->soft_iface->name);
- kref_put(&batman_if->refcount, hardif_free_ref);
+ hardif_free_ref(batman_if);
struct net_device *net_dev = kobj_to_netdev(kobj);
struct batman_if *batman_if = get_batman_if_by_netdev(net_dev);
int status_tmp = -1;
struct net_device *net_dev = kobj_to_netdev(kobj);
struct batman_if *batman_if = get_batman_if_by_netdev(net_dev);
int status_tmp = -1;
if (!batman_if)
return count;
if (!batman_if)
return count;
if (strlen(buff) >= IFNAMSIZ) {
pr_err("Invalid parameter for 'mesh_iface' setting received: "
"interface name too long '%s'\n", buff);
if (strlen(buff) >= IFNAMSIZ) {
pr_err("Invalid parameter for 'mesh_iface' setting received: "
"interface name too long '%s'\n", buff);
- kref_put(&batman_if->refcount, hardif_free_ref);
+ hardif_free_ref(batman_if);
status_tmp = IF_I_WANT_YOU;
if ((batman_if->if_status == status_tmp) || ((batman_if->soft_iface) &&
status_tmp = IF_I_WANT_YOU;
if ((batman_if->if_status == status_tmp) || ((batman_if->soft_iface) &&
- (strncmp(batman_if->soft_iface->name, buff, IFNAMSIZ) == 0))) {
- kref_put(&batman_if->refcount, hardif_free_ref);
- return count;
- }
+ (strncmp(batman_if->soft_iface->name, buff, IFNAMSIZ) == 0)))
+ goto out;
if (status_tmp == IF_NOT_IN_USE) {
rtnl_lock();
hardif_disable_interface(batman_if);
rtnl_unlock();
if (status_tmp == IF_NOT_IN_USE) {
rtnl_lock();
hardif_disable_interface(batman_if);
rtnl_unlock();
- kref_put(&batman_if->refcount, hardif_free_ref);
- return count;
}
/* if the interface already is in use */
}
/* if the interface already is in use */
}
ret = hardif_enable_interface(batman_if, buff);
}
ret = hardif_enable_interface(batman_if, buff);
- kref_put(&batman_if->refcount, hardif_free_ref);
+out:
+ hardif_free_ref(batman_if);
- kref_put(&batman_if->refcount, hardif_free_ref);
+ hardif_free_ref(batman_if);
struct packet_type *ptype,
struct net_device *orig_dev);
struct packet_type *ptype,
struct net_device *orig_dev);
-static void hardif_free_rcu(struct rcu_head *rcu)
+void hardif_free_rcu(struct rcu_head *rcu)
{
struct batman_if *batman_if;
batman_if = container_of(rcu, struct batman_if, rcu);
dev_put(batman_if->net_dev);
{
struct batman_if *batman_if;
batman_if = container_of(rcu, struct batman_if, rcu);
dev_put(batman_if->net_dev);
- kref_put(&batman_if->refcount, hardif_free_ref);
}
struct batman_if *get_batman_if_by_netdev(struct net_device *net_dev)
}
struct batman_if *get_batman_if_by_netdev(struct net_device *net_dev)
rcu_read_lock();
list_for_each_entry_rcu(batman_if, &if_list, list) {
rcu_read_lock();
list_for_each_entry_rcu(batman_if, &if_list, list) {
- if (batman_if->net_dev == net_dev)
+ if (batman_if->net_dev == net_dev &&
+ atomic_inc_not_zero(&batman_if->refcount))
goto out;
}
batman_if = NULL;
out:
goto out;
}
batman_if = NULL;
out:
- if (batman_if)
- kref_get(&batman_if->refcount);
-
rcu_read_unlock();
return batman_if;
}
rcu_read_unlock();
return batman_if;
}
if (batman_if->soft_iface != soft_iface)
continue;
if (batman_if->soft_iface != soft_iface)
continue;
- if (batman_if->if_status == IF_ACTIVE)
+ if (batman_if->if_status == IF_ACTIVE &&
+ atomic_inc_not_zero(&batman_if->refcount))
goto out;
}
batman_if = NULL;
out:
goto out;
}
batman_if = NULL;
out:
- if (batman_if)
- kref_get(&batman_if->refcount);
-
rcu_read_unlock();
return batman_if;
}
rcu_read_unlock();
return batman_if;
}
struct batman_packet *batman_packet;
struct batman_if *old_if;
struct batman_packet *batman_packet;
struct batman_if *old_if;
- if (batman_if)
- kref_get(&batman_if->refcount);
+ if (batman_if && !atomic_inc_not_zero(&batman_if->refcount))
+ batman_if = NULL;
old_if = bat_priv->primary_if;
bat_priv->primary_if = batman_if;
if (old_if)
old_if = bat_priv->primary_if;
bat_priv->primary_if = batman_if;
if (old_if)
- kref_put(&old_if->refcount, hardif_free_ref);
+ hardif_free_ref(old_if);
if (!bat_priv->primary_if)
return;
if (!bat_priv->primary_if)
return;
if (batman_if->if_status != IF_NOT_IN_USE)
goto out;
if (batman_if->if_status != IF_NOT_IN_USE)
goto out;
+ if (!atomic_inc_not_zero(&batman_if->refcount))
+ goto out;
+
batman_if->soft_iface = dev_get_by_name(&init_net, iface_name);
if (!batman_if->soft_iface) {
batman_if->soft_iface = dev_get_by_name(&init_net, iface_name);
if (!batman_if->soft_iface) {
batman_if->batman_adv_ptype.type = __constant_htons(ETH_P_BATMAN);
batman_if->batman_adv_ptype.func = batman_skb_recv;
batman_if->batman_adv_ptype.dev = batman_if->net_dev;
batman_if->batman_adv_ptype.type = __constant_htons(ETH_P_BATMAN);
batman_if->batman_adv_ptype.func = batman_skb_recv;
batman_if->batman_adv_ptype.dev = batman_if->net_dev;
- kref_get(&batman_if->refcount);
dev_add_pack(&batman_if->batman_adv_ptype);
atomic_set(&batman_if->seqno, 1);
dev_add_pack(&batman_if->batman_adv_ptype);
atomic_set(&batman_if->seqno, 1);
+ hardif_free_ref(batman_if);
bat_info(batman_if->soft_iface, "Removing interface: %s\n",
batman_if->net_dev->name);
dev_remove_pack(&batman_if->batman_adv_ptype);
bat_info(batman_if->soft_iface, "Removing interface: %s\n",
batman_if->net_dev->name);
dev_remove_pack(&batman_if->batman_adv_ptype);
- kref_put(&batman_if->refcount, hardif_free_ref);
bat_priv->num_ifaces--;
orig_hash_del_if(batman_if, bat_priv->num_ifaces);
bat_priv->num_ifaces--;
orig_hash_del_if(batman_if, bat_priv->num_ifaces);
set_primary_if(bat_priv, new_if);
if (new_if)
set_primary_if(bat_priv, new_if);
if (new_if)
- kref_put(&new_if->refcount, hardif_free_ref);
+ hardif_free_ref(new_if);
}
kfree(batman_if->packet_buff);
}
kfree(batman_if->packet_buff);
softif_destroy(batman_if->soft_iface);
batman_if->soft_iface = NULL;
softif_destroy(batman_if->soft_iface);
batman_if->soft_iface = NULL;
+ hardif_free_ref(batman_if);
}
static struct batman_if *hardif_add_interface(struct net_device *net_dev)
}
static struct batman_if *hardif_add_interface(struct net_device *net_dev)
batman_if->soft_iface = NULL;
batman_if->if_status = IF_NOT_IN_USE;
INIT_LIST_HEAD(&batman_if->list);
batman_if->soft_iface = NULL;
batman_if->if_status = IF_NOT_IN_USE;
INIT_LIST_HEAD(&batman_if->list);
- kref_init(&batman_if->refcount);
+ /* extra reference for return */
+ atomic_set(&batman_if->refcount, 2);
check_known_mac_addr(batman_if->net_dev);
check_known_mac_addr(batman_if->net_dev);
list_add_tail_rcu(&batman_if->list, &if_list);
spin_unlock(&if_list_lock);
list_add_tail_rcu(&batman_if->list, &if_list);
spin_unlock(&if_list_lock);
- /* extra reference for return */
- kref_get(&batman_if->refcount);
return batman_if;
free_if:
return batman_if;
free_if:
batman_if->if_status = IF_TO_BE_REMOVED;
sysfs_del_hardif(&batman_if->hardif_obj);
batman_if->if_status = IF_TO_BE_REMOVED;
sysfs_del_hardif(&batman_if->hardif_obj);
- call_rcu(&batman_if->rcu, hardif_free_rcu);
+ hardif_free_ref(batman_if);
}
void hardif_remove_interfaces(void)
}
void hardif_remove_interfaces(void)
- kref_put(&batman_if->refcount, hardif_free_ref);
+ hardif_free_ref(batman_if);
out:
return NOTIFY_DONE;
}
out:
return NOTIFY_DONE;
}
void hardif_remove_interfaces(void);
int hardif_min_mtu(struct net_device *soft_iface);
void update_min_mtu(struct net_device *soft_iface);
void hardif_remove_interfaces(void);
int hardif_min_mtu(struct net_device *soft_iface);
void update_min_mtu(struct net_device *soft_iface);
+void hardif_free_rcu(struct rcu_head *rcu);
-static inline void hardif_free_ref(struct kref *refcount)
+static inline void hardif_free_ref(struct batman_if *batman_if)
- struct batman_if *batman_if;
-
- batman_if = container_of(refcount, struct batman_if, refcount);
- kfree(batman_if);
+ if (atomic_dec_and_test(&batman_if->refcount))
+ call_rcu(&batman_if->rcu, hardif_free_rcu);
}
#endif /* _NET_BATMAN_ADV_HARD_INTERFACE_H_ */
}
#endif /* _NET_BATMAN_ADV_HARD_INTERFACE_H_ */
unsigned char *packet_buff;
int packet_len;
struct kobject *hardif_obj;
unsigned char *packet_buff;
int packet_len;
struct kobject *hardif_obj;
struct packet_type batman_adv_ptype;
struct net_device *soft_iface;
struct rcu_head rcu;
struct packet_type batman_adv_ptype;
struct net_device *soft_iface;
struct rcu_head rcu;