Return-path: Received: from mail.tpi.com ([70.99.223.143]:4851 "EHLO mail.tpi.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755492Ab2LFUtF (ORCPT ); Thu, 6 Dec 2012 15:49:05 -0500 From: Tim Gardner To: linux-kernel@vger.kernel.org Cc: Tim Gardner , Johannes Berg , Wey-Yi Guy , Intel Linux Wireless , "John W. Linville" , Emmanuel Grumbach , Don Fry , linux-wireless@vger.kernel.org, netdev@vger.kernel.org Subject: [PATCH wireless-next] iwlwifi: iwlagn_request_scan: Fix check for NULL priv->scan_request Date: Thu, 6 Dec 2012 13:24:05 -0700 Message-Id: <1354825445-79551-1-git-send-email-tim.gardner@canonical.com> (sfid-20121206_214912_422543_9C67DD48) Sender: linux-wireless-owner@vger.kernel.org List-ID: The WARN_ON_ONCE() check for scan_request will not correctly detect a NULL pointer for scan_type == IWL_SCAN_NORMAL. Make it explicit that the check only applies to normal scans. Convert WARN_ON_ONCE to WARN_ON since priv->scan_request really _can't_ be NULL for normal scans. If it is then we should emit frequent warnings. This smatch warning led to scrutiny of iwlagn_request_scan(): drivers/net/wireless/iwlwifi/dvm/scan.c:894 iwlagn_request_scan() error: we previously assumed 'priv->scan_request' could be null (see line 792) Cc: Johannes Berg Cc: Wey-Yi Guy Cc: Intel Linux Wireless Cc: "John W. Linville" Cc: Emmanuel Grumbach Cc: Don Fry Cc: linux-wireless@vger.kernel.org Cc: netdev@vger.kernel.org Signed-off-by: Tim Gardner --- This patch does apply to 3.6.y, but it doesn't fix an existing bug so I don't think it qualifies. This patch simply makes the driver more robust for future development. drivers/net/wireless/iwlwifi/dvm/scan.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/net/wireless/iwlwifi/dvm/scan.c b/drivers/net/wireless/iwlwifi/dvm/scan.c index bb9f625..e5cbcca 100644 --- a/drivers/net/wireless/iwlwifi/dvm/scan.c +++ b/drivers/net/wireless/iwlwifi/dvm/scan.c @@ -673,8 +673,9 @@ static int iwlagn_request_scan(struct iwl_priv *priv, struct ieee80211_vif *vif) const u8 *ssid = NULL; u8 ssid_len = 0; - if (WARN_ON_ONCE(priv->scan_request && - priv->scan_request->n_channels > MAX_SCAN_CHANNEL)) + if (WARN_ON(priv->scan_type == IWL_SCAN_NORMAL && + (!priv->scan_request || + priv->scan_request->n_channels > MAX_SCAN_CHANNEL))) return -EINVAL; lockdep_assert_held(&priv->mutex); -- 1.7.9.5