[2/2] batman-adv: Avoid deadlock between rtnl_lock and s_active
Commit Message
The hard_if_event is called by the notifier with rtnl_lock and tries to
remove sysfs entries when a NETDEV_UNREGISTER event is received. This
will automatically take the s_active lock.
The s_active lock is also used when a new interface is added to a meshif
through sysfs. In that situation we cannot wait for the rntl_lock before
creating the actual batman-adv interface to prevent a deadlock. It is
still possible to try to get the rtnl_lock and immediately abort the
current operation when the trylock call failed.
Signed-off-by: Sven Eckelmann <sven@narfation.org>
---
bat_sysfs.c | 13 ++++++++-----
soft-interface.c | 2 +-
2 files changed, 9 insertions(+), 6 deletions(-)
@@ -488,22 +488,25 @@ static ssize_t store_mesh_iface(struct kobject *kobj, struct attribute *attr,
(strncmp(hard_iface->soft_iface->name, buff, IFNAMSIZ) == 0))
goto out;
+ if (!rtnl_trylock()) {
+ ret = -ERESTARTSYS;
+ goto out;
+ }
+
if (status_tmp == IF_NOT_IN_USE) {
- rtnl_lock();
hardif_disable_interface(hard_iface);
- rtnl_unlock();
- goto out;
+ goto unlock;
}
/* if the interface already is in use */
if (hard_iface->if_status != IF_NOT_IN_USE) {
- rtnl_lock();
hardif_disable_interface(hard_iface);
- rtnl_unlock();
}
ret = hardif_enable_interface(hard_iface, buff);
+unlock:
+ rtnl_unlock();
out:
hardif_free_ref(hard_iface);
return ret;
@@ -613,7 +613,7 @@ struct net_device *softif_create(char *name)
goto out;
}
- ret = register_netdev(soft_iface);
+ ret = register_netdevice(soft_iface);
if (ret < 0) {
pr_err("Unable to register the batman interface '%s': %i\n",
name, ret);