From patchwork Tue May 3 11:10:06 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: =?utf-8?q?Linus_L=C3=BCssing?= X-Patchwork-Id: 999 Return-Path: Received: from fmmailgate01.web.de (fmmailgate01.web.de [217.72.192.221]) by open-mesh.org (Postfix) with ESMTP id BE1A41541F6 for ; Tue, 3 May 2011 13:19:11 +0200 (CEST) Received: from smtp04.web.de ( [172.20.0.225]) by fmmailgate01.web.de (Postfix) with ESMTP id 178FB18DF719A; Tue, 3 May 2011 13:09:55 +0200 (CEST) Received: from [141.83.65.188] (helo=localhost) by smtp04.web.de with asmtp (TLSv1:AES128-SHA:128) (WEB.DE 4.110 #2) id 1QHDUI-0003sc-00; Tue, 03 May 2011 13:09:54 +0200 From: =?UTF-8?q?Linus=20L=C3=BCssing?= To: b.a.t.m.a.n@lists.open-mesh.org Date: Tue, 3 May 2011 13:10:06 +0200 Message-Id: <1304421006-7137-1-git-send-email-linus.luessing@web.de> X-Mailer: git-send-email 1.7.4.1 In-Reply-To: <1304416299-906-2-git-send-email-linus.luessing@web.de> References: <1304416299-906-2-git-send-email-linus.luessing@web.de> Sender: linus.luessing@web.de X-Sender: linus.luessing@web.de X-Provags-ID: V01U2FsdGVkX18EC9mlRWxqxsDtn6XqAEMPxcN3oF/GyVIyzrmk igBqJTYUCALxWavGsQQUxsToTeSKbdeu4DUtVsAb8z/ryDZ3M6 5H7PHXh3Yfd59e7XARPA== Subject: [B.A.T.M.A.N.] [PATCH 2/2] batman-adv: Avoid deadlock between rtnl_lock and s_active X-BeenThere: b.a.t.m.a.n@lists.open-mesh.org X-Mailman-Version: 2.1.13 Precedence: list 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: , X-List-Received-Date: Tue, 03 May 2011 11:19:11 -0000 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;