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authorSven Eckelmann <sven@narfation.org>2011-05-03 13:10:06 +0200
committerSven Eckelmann <sven@narfation.org>2011-05-08 16:10:42 +0200
commit3a4375a9f0080e6ae40af63e2e2c1e70a6dcb775 (patch)
treea3448104babf921c217a1e94c2e46d5bd7613a2d /net/batman-adv
parentc3caf5196c47a5d1c325308d8eb7f6b020ba12df (diff)
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>
Diffstat (limited to 'net/batman-adv')
-rw-r--r--net/batman-adv/bat_sysfs.c18
1 files changed, 9 insertions, 9 deletions
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;