[linux-next] LinuxNextTracking branch, master, updated. next-20110624

batman at open-mesh.org batman at open-mesh.org
Fri Jun 24 16:09:30 CEST 2011

The following commit has been merged in the master branch:
commit 3a4375a9f0080e6ae40af63e2e2c1e70a6dcb775
Author: Sven Eckelmann <sven at 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 at 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();
-		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)
-		rtnl_unlock();
-	}
-	rtnl_lock();
 	ret = hardif_enable_interface(hard_iface, buff);
-	rtnl_unlock();
+	rtnl_unlock();
 	return ret;


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