From 88be026490ed89c2ffead81a52531fbac5507e01 Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Wed, 7 Apr 2010 00:21:36 -0700 Subject: iwlwifi: fix scan races When an internal scan is started, nothing protects the is_internal_short_scan variable which can cause crashes, cf. https://bugzilla.kernel.org/show_bug.cgi?id=15667. Fix this by making the short scan request use the mutex for locking, which requires making the request go to a work struct so that it can sleep. Reported-by: Peter Zijlstra Signed-off-by: Johannes Berg Signed-off-by: Reinette Chatre --- drivers/net/wireless/iwlwifi/iwl-scan.c | 31 ++++++++++++++++++++----------- 1 file changed, 20 insertions(+), 11 deletions(-) (limited to 'drivers/net/wireless/iwlwifi/iwl-scan.c') diff --git a/drivers/net/wireless/iwlwifi/iwl-scan.c b/drivers/net/wireless/iwlwifi/iwl-scan.c index bd2f7c42056..5062f4ebb6a 100644 --- a/drivers/net/wireless/iwlwifi/iwl-scan.c +++ b/drivers/net/wireless/iwlwifi/iwl-scan.c @@ -469,6 +469,8 @@ EXPORT_SYMBOL(iwl_init_scan_params); static int iwl_scan_initiate(struct iwl_priv *priv) { + WARN_ON(!mutex_is_locked(&priv->mutex)); + IWL_DEBUG_INFO(priv, "Starting scan...\n"); set_bit(STATUS_SCANNING, &priv->status); priv->is_internal_short_scan = false; @@ -546,24 +548,31 @@ EXPORT_SYMBOL(iwl_mac_hw_scan); * internal short scan, this function should only been called while associated. * It will reset and tune the radio to prevent possible RF related problem */ -int iwl_internal_short_hw_scan(struct iwl_priv *priv) +void iwl_internal_short_hw_scan(struct iwl_priv *priv) { - int ret = 0; + queue_work(priv->workqueue, &priv->start_internal_scan); +} + +static void iwl_bg_start_internal_scan(struct work_struct *work) +{ + struct iwl_priv *priv = + container_of(work, struct iwl_priv, start_internal_scan); + + mutex_lock(&priv->mutex); if (!iwl_is_ready_rf(priv)) { - ret = -EIO; IWL_DEBUG_SCAN(priv, "not ready or exit pending\n"); - goto out; + goto unlock; } + if (test_bit(STATUS_SCANNING, &priv->status)) { IWL_DEBUG_SCAN(priv, "Scan already in progress.\n"); - ret = -EAGAIN; - goto out; + goto unlock; } + if (test_bit(STATUS_SCAN_ABORTING, &priv->status)) { IWL_DEBUG_SCAN(priv, "Scan request while abort pending\n"); - ret = -EAGAIN; - goto out; + goto unlock; } priv->scan_bands = 0; @@ -576,9 +585,8 @@ int iwl_internal_short_hw_scan(struct iwl_priv *priv) set_bit(STATUS_SCANNING, &priv->status); priv->is_internal_short_scan = true; queue_work(priv->workqueue, &priv->request_scan); - -out: - return ret; + unlock: + mutex_unlock(&priv->mutex); } EXPORT_SYMBOL(iwl_internal_short_hw_scan); @@ -964,6 +972,7 @@ void iwl_setup_scan_deferred_work(struct iwl_priv *priv) INIT_WORK(&priv->scan_completed, iwl_bg_scan_completed); INIT_WORK(&priv->request_scan, iwl_bg_request_scan); INIT_WORK(&priv->abort_scan, iwl_bg_abort_scan); + INIT_WORK(&priv->start_internal_scan, iwl_bg_start_internal_scan); INIT_DELAYED_WORK(&priv->scan_check, iwl_bg_scan_check); } EXPORT_SYMBOL(iwl_setup_scan_deferred_work); -- cgit v1.2.3