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Commit f4acb108 authored by Sven Eckelmann's avatar Sven Eckelmann Committed by Simon Wunderlich
Browse files

batman-adv: Avoid sysfs name collision for netns moves 



The kobject_put is only removing the sysfs entry and corresponding entries
when its reference counter becomes zero. This tends to lead to collisions
when a device is moved between two different network namespaces because
some of the sysfs files have to be removed first and then added again to
the already moved sysfs entry.

    WARNING: CPU: 0 PID: 290 at lib/kobject.c:240 kobject_add_internal+0x5ec/0x8a0
    kobject_add_internal failed for batman_adv with -EEXIST, don't try to register things with the same name in the same directory.

But the caller of kobject_put can already remove the sysfs entry before it
does the kobject_put. This removal is done even when the reference counter
is not yet zero and thus avoids the problem.

Signed-off-by: default avatarSven Eckelmann <sven@narfation.org>
Signed-off-by: default avatarMarek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: default avatarSimon Wunderlich <sw@simonwunderlich.de>
parent 569c9850

net/batman-adv/sysfs.c

+14 −0
Original line number Diff line number Diff line
@@ -713,6 +713,8 @@ int batadv_sysfs_add_meshif(struct net_device *dev) 
	for (bat_attr = batadv_mesh_attrs; *bat_attr; ++bat_attr)

		sysfs_remove_file(bat_priv->mesh_obj, &((*bat_attr)->attr));



	kobject_uevent(bat_priv->mesh_obj, KOBJ_REMOVE);

	kobject_del(bat_priv->mesh_obj);

	kobject_put(bat_priv->mesh_obj);

	bat_priv->mesh_obj = NULL;

out:
@@ -727,6 +729,8 @@ void batadv_sysfs_del_meshif(struct net_device *dev) 
	for (bat_attr = batadv_mesh_attrs; *bat_attr; ++bat_attr)

		sysfs_remove_file(bat_priv->mesh_obj, &((*bat_attr)->attr));



	kobject_uevent(bat_priv->mesh_obj, KOBJ_REMOVE);

	kobject_del(bat_priv->mesh_obj);

	kobject_put(bat_priv->mesh_obj);

	bat_priv->mesh_obj = NULL;

}
@@ -782,6 +786,10 @@ int batadv_sysfs_add_vlan(struct net_device *dev, 
	for (bat_attr = batadv_vlan_attrs; *bat_attr; ++bat_attr)

		sysfs_remove_file(vlan->kobj, &((*bat_attr)->attr));



	if (vlan->kobj != bat_priv->mesh_obj) {

		kobject_uevent(vlan->kobj, KOBJ_REMOVE);

		kobject_del(vlan->kobj);

	}

	kobject_put(vlan->kobj);

	vlan->kobj = NULL;

out:
@@ -801,6 +809,10 @@ void batadv_sysfs_del_vlan(struct batadv_priv *bat_priv, 
	for (bat_attr = batadv_vlan_attrs; *bat_attr; ++bat_attr)

		sysfs_remove_file(vlan->kobj, &((*bat_attr)->attr));



	if (vlan->kobj != bat_priv->mesh_obj) {

		kobject_uevent(vlan->kobj, KOBJ_REMOVE);

		kobject_del(vlan->kobj);

	}

	kobject_put(vlan->kobj);

	vlan->kobj = NULL;

}
@@ -1103,6 +1115,8 @@ int batadv_sysfs_add_hardif(struct kobject **hardif_obj, struct net_device *dev) 


void batadv_sysfs_del_hardif(struct kobject **hardif_obj)

{

	kobject_uevent(*hardif_obj, KOBJ_REMOVE);

	kobject_del(*hardif_obj);

	kobject_put(*hardif_obj);

	*hardif_obj = NULL;

}