Commit 3a4375a9 authored by Sven Eckelmann's avatar Sven Eckelmann

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: default avatarSven Eckelmann <sven@narfation.org>
parent c3caf519
...@@ -488,24 +488,24 @@ static ssize_t store_mesh_iface(struct kobject *kobj, struct attribute *attr, ...@@ -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)) (strncmp(hard_iface->soft_iface->name, buff, IFNAMSIZ) == 0))
goto out; goto out;
if (!rtnl_trylock()) {
ret = -ERESTARTSYS;
goto out;
}
if (status_tmp == IF_NOT_IN_USE) { if (status_tmp == IF_NOT_IN_USE) {
rtnl_lock();
hardif_disable_interface(hard_iface); hardif_disable_interface(hard_iface);
rtnl_unlock(); goto unlock;
goto out;
} }
/* if the interface already is in use */ /* if the interface already is in use */
if (hard_iface->if_status != IF_NOT_IN_USE) { if (hard_iface->if_status != IF_NOT_IN_USE)
rtnl_lock();
hardif_disable_interface(hard_iface); hardif_disable_interface(hard_iface);
rtnl_unlock();
}
rtnl_lock();
ret = hardif_enable_interface(hard_iface, buff); ret = hardif_enable_interface(hard_iface, buff);
rtnl_unlock();
unlock:
rtnl_unlock();
out: out:
hardif_free_ref(hard_iface); hardif_free_ref(hard_iface);
return ret; return ret;
......
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