From: Sven Eckelmann Date: Tue, 3 May 2011 11:10:06 +0000 (+0200) Subject: batman-adv: Avoid deadlock between rtnl_lock and s_active X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=3a4375a9f0080e6ae40af63e2e2c1e70a6dcb775;p=GitHub%2Fexynos8895%2Fandroid_kernel_samsung_universal8895.git 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 --- diff --git a/net/batman-adv/bat_sysfs.c b/net/batman-adv/bat_sysfs.c index 85ba20d98a66..497a0700cc3c 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;