From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761499Ab3EFXps (ORCPT ); Mon, 6 May 2013 19:45:48 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:36209 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932896Ab3EFW50 (ORCPT ); Mon, 6 May 2013 18:57:26 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Johannes Berg Subject: [ 51/63] wireless: regulatory: fix channel disabling race condition Date: Mon, 6 May 2013 15:56:29 -0700 Message-Id: <20130506225327.104727909@linuxfoundation.org> X-Mailer: git-send-email 1.8.3.rc0.20.gb99dd2e In-Reply-To: <20130506225314.802167948@linuxfoundation.org> References: <20130506225314.802167948@linuxfoundation.org> User-Agent: quilt/0.60-5.1.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Johannes Berg commit 990de49f74e772b6db5208457b7aa712a5f4db86 upstream. When a full scan 2.4 and 5 GHz scan is scheduled, but then the 2.4 GHz part of the scan disables a 5.2 GHz channel due to, e.g. receiving country or frequency information, that 5.2 GHz channel might already be in the list of channels to scan next. Then, when the driver checks if it should do a passive scan, that will return false and attempt an active scan. This is not only wrong but can also lead to the iwlwifi device firmware crashing since it checks regulatory as well. Fix this by not setting the channel flags to just disabled but rather OR'ing in the disabled flag. That way, even if the race happens, the channel will be scanned passively which is still (mostly) correct. Signed-off-by: Johannes Berg Signed-off-by: Greg Kroah-Hartman --- net/wireless/reg.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/net/wireless/reg.c +++ b/net/wireless/reg.c @@ -862,7 +862,7 @@ static void handle_channel(struct wiphy return; REG_DBG_PRINT("Disabling freq %d MHz\n", chan->center_freq); - chan->flags = IEEE80211_CHAN_DISABLED; + chan->flags |= IEEE80211_CHAN_DISABLED; return; }