From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: =?UTF-8?q?Linus=20L=C3=BCssing?= Date: Tue, 3 May 2011 11:51:39 +0200 Message-Id: <1304416299-906-3-git-send-email-linus.luessing@web.de> In-Reply-To: <1304416299-906-1-git-send-email-linus.luessing@web.de> References: <1304363978-16164-1-git-send-email-sven@narfation.org> <1304416299-906-1-git-send-email-linus.luessing@web.de> Sender: linus.luessing@web.de Subject: [B.A.T.M.A.N.] [PATCH 2/2] batman-adv: Avoid deadlock between rtnl_lock and s_active Reply-To: The list for a Better Approach To Mobile Ad-hoc Networking List-Id: The list for a Better Approach To Mobile Ad-hoc Networking List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: b.a.t.m.a.n@lists.open-mesh.org From: Sven Eckelmann 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 --- bat_sysfs.c | 18 +++++++++--------- 1 files changed, 9 insertions(+), 9 deletions(-) diff --git a/bat_sysfs.c b/bat_sysfs.c index 85ba20d..497a070 100644 --- a/bat_sysfs.c +++ b/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; -- 1.7.4.1