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Commit 5bc44dc8 authored by Simon Wunderlich's avatar Simon Wunderlich Committed by Antonio Quartulli
Browse files

batman-adv: postpone sysfs removal when unregistering 



When processing the unregister notify for a hard interface, removing
the sysfs files may lead to a circular deadlock (rtnl mutex <->
s_active).

To overcome this problem, postpone the sysfs removal in a worker.

Reported-by: default avatarSasha Levin <sasha.levin@oracle.com>
Reported-by: default avatarSven Eckelmann <sven@narfation.org>
Signed-off-by: default avatarSimon Wunderlich <siwu@hrz.tu-chemnitz.de>
Signed-off-by: default avatarMarek Lindner <lindner_marek@yahoo.de>
Signed-off-by: default avatarAntonio Quartulli <ordex@autistici.org>
parent e76e4320

net/batman-adv/hard-interface.c

+22 −2
Original line number Diff line number Diff line
@@ -457,6 +457,24 @@ void batadv_hardif_disable_interface(struct batadv_hard_iface *hard_iface) 
		batadv_hardif_free_ref(primary_if);

}



/**

 * batadv_hardif_remove_interface_finish - cleans up the remains of a hardif

 * @work: work queue item

 *

 * Free the parts of the hard interface which can not be removed under

 * rtnl lock (to prevent deadlock situations).

 */

static void batadv_hardif_remove_interface_finish(struct work_struct *work)

{

	struct batadv_hard_iface *hard_iface;



	hard_iface = container_of(work, struct batadv_hard_iface,

				  cleanup_work);



	batadv_sysfs_del_hardif(&hard_iface->hardif_obj);

	batadv_hardif_free_ref(hard_iface);

}



static struct batadv_hard_iface *

batadv_hardif_add_interface(struct net_device *net_dev)

{
@@ -484,6 +502,9 @@ batadv_hardif_add_interface(struct net_device *net_dev) 
	hard_iface->soft_iface = NULL;

	hard_iface->if_status = BATADV_IF_NOT_IN_USE;

	INIT_LIST_HEAD(&hard_iface->list);

	INIT_WORK(&hard_iface->cleanup_work,

		  batadv_hardif_remove_interface_finish);



	/* extra reference for return */

	atomic_set(&hard_iface->refcount, 2);
@@ -518,8 +539,7 @@ static void batadv_hardif_remove_interface(struct batadv_hard_iface *hard_iface) 
		return;



	hard_iface->if_status = BATADV_IF_TO_BE_REMOVED;

	batadv_sysfs_del_hardif(&hard_iface->hardif_obj);

	batadv_hardif_free_ref(hard_iface);

	queue_work(batadv_event_workqueue, &hard_iface->cleanup_work);

}



void batadv_hardif_remove_interfaces(void)

net/batman-adv/soft-interface.c

+29 −3
Original line number Diff line number Diff line
@@ -449,6 +449,30 @@ static void batadv_interface_setup(struct net_device *dev) 
	memset(priv, 0, sizeof(*priv));

}



/**

 * batadv_softif_destroy_finish - cleans up the remains of a softif

 * @work: work queue item

 *

 * Free the parts of the soft interface which can not be removed under

 * rtnl lock (to prevent deadlock situations).

 */

static void batadv_softif_destroy_finish(struct work_struct *work)

{

	struct batadv_priv *bat_priv;

	struct net_device *soft_iface;



	bat_priv = container_of(work, struct batadv_priv,

				cleanup_work);

	soft_iface = bat_priv->soft_iface;



	batadv_debugfs_del_meshif(soft_iface);

	batadv_sysfs_del_meshif(soft_iface);



	rtnl_lock();

	unregister_netdevice(soft_iface);

	rtnl_unlock();

}



struct net_device *batadv_softif_create(const char *name)

{

	struct net_device *soft_iface;
@@ -463,6 +487,8 @@ struct net_device *batadv_softif_create(const char *name) 
		goto out;



	bat_priv = netdev_priv(soft_iface);

	bat_priv->soft_iface = soft_iface;

	INIT_WORK(&bat_priv->cleanup_work, batadv_softif_destroy_finish);



	/* batadv_interface_stats() needs to be available as soon as

	 * register_netdevice() has been called
@@ -551,10 +577,10 @@ struct net_device *batadv_softif_create(const char *name) 


void batadv_softif_destroy(struct net_device *soft_iface)

{

	batadv_debugfs_del_meshif(soft_iface);

	batadv_sysfs_del_meshif(soft_iface);

	struct batadv_priv *bat_priv = netdev_priv(soft_iface);



	batadv_mesh_free(soft_iface);

	unregister_netdevice(soft_iface);

	queue_work(batadv_event_workqueue, &bat_priv->cleanup_work);

}



int batadv_softif_is_valid(const struct net_device *net_dev)

net/batman-adv/types.h

+6 −0
Original line number Diff line number Diff line
@@ -68,6 +68,7 @@ struct batadv_hard_iface_bat_iv { 
 * @soft_iface: the batman-adv interface which uses this network interface

 * @rcu: struct used for freeing in an RCU-safe manner

 * @bat_iv: BATMAN IV specific per hard interface data

 * @cleanup_work: work queue callback item for hard interface deinit

 */

struct batadv_hard_iface {

	struct list_head list;
@@ -81,6 +82,7 @@ struct batadv_hard_iface { 
	struct net_device *soft_iface;

	struct rcu_head rcu;

	struct batadv_hard_iface_bat_iv bat_iv;

	struct work_struct cleanup_work;

};



/**
@@ -428,6 +430,7 @@ struct batadv_priv_dat { 
/**

 * struct batadv_priv - per mesh interface data

 * @mesh_state: current status of the mesh (inactive/active/deactivating)

 * @soft_iface: net device which holds this struct as private data

 * @stats: structure holding the data for the ndo_get_stats() call

 * @bat_counters: mesh internal traffic statistic counters (see batadv_counters)

 * @aggregated_ogms: bool indicating whether OGM aggregation is enabled
@@ -457,6 +460,7 @@ struct batadv_priv_dat { 
 * @forw_bat_list_lock: lock protecting forw_bat_list

 * @forw_bcast_list_lock: lock protecting forw_bcast_list

 * @orig_work: work queue callback item for orig node purging

 * @cleanup_work: work queue callback item for soft interface deinit

 * @primary_if: one of the hard interfaces assigned to this mesh interface

 *  becomes the primary interface

 * @bat_algo_ops: routing algorithm used by this mesh interface
@@ -469,6 +473,7 @@ struct batadv_priv_dat { 
 */

struct batadv_priv {

	atomic_t mesh_state;

	struct net_device *soft_iface;

	struct net_device_stats stats;

	uint64_t __percpu *bat_counters; /* Per cpu counters */

	atomic_t aggregated_ogms;
@@ -502,6 +507,7 @@ struct batadv_priv { 
	spinlock_t forw_bat_list_lock; /* protects forw_bat_list */

	spinlock_t forw_bcast_list_lock; /* protects forw_bcast_list */

	struct delayed_work orig_work;

	struct work_struct cleanup_work;

	struct batadv_hard_iface __rcu *primary_if;  /* rcu protected pointer */

	struct batadv_algo_ops *bat_algo_ops;

#ifdef CONFIG_BATMAN_ADV_BLA