The following commit has been merged in the master branch: commit 3a4375a9f0080e6ae40af63e2e2c1e70a6dcb775 Author: Sven Eckelmann sven@narfation.org Date: Tue May 3 13:10:06 2011 +0200

batman-adv: Avoid deadlock between rtnl_lock and s_active

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

diff --git a/net/batman-adv/bat_sysfs.c b/net/batman-adv/bat_sysfs.c index 85ba20d..497a070 100644 --- a/net/batman-adv/bat_sysfs.c +++ b/net/batman-adv/bat_sysfs.c @@ -488,24 +488,24 @@ 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(); + if (hard_iface->if_status != IF_NOT_IN_USE) hardif_disable_interface(hard_iface); - rtnl_unlock(); - }

- rtnl_lock(); ret = hardif_enable_interface(hard_iface, buff); - rtnl_unlock();

+unlock: + rtnl_unlock(); out: hardif_free_ref(hard_iface); return ret;