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>
Signed-off-by: Antonio Quartulli <ordex@autistici.org>
diff --git a/net/batman-adv/soft-interface.c b/net/batman-adv/soft-interface.c
index 3d68166..c9962fe 100644
--- a/net/batman-adv/soft-interface.c
+++ b/net/batman-adv/soft-interface.c
@@ -449,6 +449,30 @@
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 @@
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 @@
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)