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

On branch : master

commit a33c882c10692b99ce647c929cb90c62e87fa083 Author: Simon Wunderlich simon.wunderlich@s2003.tu-chemnitz.de Date: Fri Jan 11 10:19:51 2013 +0100

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: Sasha Levin sasha.levin@oracle.com Reported-by: Sven Eckelmann sven@narfation.org Signed-off-by: Simon Wunderlich siwu@hrz.tu-chemnitz.de Signed-off-by: Marek Lindner lindner_marek@yahoo.de

a33c882c10692b99ce647c929cb90c62e87fa083 hard-interface.c | 24 ++++++++++++++++++++++-- soft-interface.c | 32 +++++++++++++++++++++++++++++--- types.h | 6 ++++++ 3 files changed, 57 insertions(+), 5 deletions(-)

diff --git a/hard-interface.c b/hard-interface.c index 78cf350..368219e 100644 --- a/hard-interface.c +++ b/hard-interface.c @@ -457,6 +457,24 @@ out: 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) diff --git a/soft-interface.c b/soft-interface.c index e67e013..2711e87 100644 --- a/soft-interface.c +++ b/soft-interface.c @@ -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 @@ out:

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) diff --git a/types.h b/types.h index 89ac1fb..4cd87a0 100644 --- a/types.h +++ b/types.h @@ -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