Return-path: Received: from fmmailgate03.web.de ([217.72.192.234]:53226 "EHLO fmmailgate03.web.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750771AbZC1AqT (ORCPT ); Fri, 27 Mar 2009 20:46:19 -0400 From: Christian Lamparter To: linux-wireless@vger.kernel.org, "John W. Linville" Subject: [PATCH] ar9170: fix hang on stop Date: Sat, 28 Mar 2009 01:46:14 +0100 MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Message-Id: <200903280146.14903.chunkeey@web.de> (sfid-20090328_014623_005708_BD67BF74) Sender: linux-wireless-owner@vger.kernel.org List-ID: This patch fixes a locking problem which freezes the network core. The deadlock goes as follows: - ar9170_op_stop - is called 1. change the state to IDLE 2. > take the MUTEX < 3. cancel_SYNC all pending work, which means "block until a work_struct's callback has terminated" => if filter_config_work was queued it tries to get the MUTEX, before checking the device state... Signed-off-by: Christian Lamparter --- John, I guess you have to queue this for the next wireless-2.6 ;) By the way, I guess you should add the p54spi fixes as well. Regards, Chr --- diff --git a/drivers/net/wireless/ar9170/main.c b/drivers/net/wireless/ar9170/main.c index 5996ff9..5f55754 100644 --- a/drivers/net/wireless/ar9170/main.c +++ b/drivers/net/wireless/ar9170/main.c @@ -742,8 +742,9 @@ static void ar9170_op_stop(struct ieee80211_hw *hw) if (IS_STARTED(ar)) ar->state = AR9170_IDLE; - mutex_lock(&ar->mutex); + flush_workqueue(ar->hw->workqueue); + mutex_lock(&ar->mutex); cancel_delayed_work_sync(&ar->tx_status_janitor); cancel_work_sync(&ar->filter_config_work); cancel_work_sync(&ar->beacon_work); @@ -1123,10 +1124,10 @@ static void ar9170_set_filters(struct work_struct *work) filter_config_work); int err; - mutex_lock(&ar->mutex); if (unlikely(!IS_STARTED(ar))) - goto unlock; + return ; + mutex_lock(&ar->mutex); if (ar->filter_changed & AR9170_FILTER_CHANGED_PROMISC) { err = ar9170_set_operating_mode(ar); if (err)