Return-path: Received: from mail.atheros.com ([12.36.123.2]:17368 "EHLO mail.atheros.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751629AbZCPHne (ORCPT ); Mon, 16 Mar 2009 03:43:34 -0400 Received: from mail.atheros.com ([10.10.20.105]) by sidewinder.atheros.com for ; Mon, 16 Mar 2009 00:43:33 -0700 From: Sujith MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Message-ID: <18878.551.886600.777650@gargle.gargle.HOWL> (sfid-20090316_084341_295452_62AB83A0) Date: Mon, 16 Mar 2009 13:09:19 +0530 To: Johannes Berg CC: Bob Copeland , "linville@tuxdriver.com" , "linux-wireless@vger.kernel.org" , Jouni Malinen Subject: Re: [PATCH] mac80211: Tear down aggregation sessions for suspend/resume In-Reply-To: <1237187728.27769.2.camel@johannes.local> References: <18876.41851.397740.847705@gargle.gargle.HOWL> <1237140134.24621.0.camel@johannes.local> <18877.56125.181203.703218@gargle.gargle.HOWL> <1237187728.27769.2.camel@johannes.local> Sender: linux-wireless-owner@vger.kernel.org List-ID: Johannes Berg wrote: > > There is a window for a race. Something like this: > > > > From mac80211: > > > > __ieee80211_suspend() > > tear_down_BA_sessions(TX, RX) > > ampdu_action(STOP) > > remove_vifs() > > > > At this point, the driver executes its remove_interface routine. > > While we are doing this, a TX completion interrupt could be raised, > > (HW hasn't been stopped yet) and nothing stops the driver from calling > > ieee80211_start_tx_ba_session(). > > > > So the question is: should mac80211 deny ADDBA requests in this case ? > > Interesting observation. We probably should indeed reject that, and also > if the peer asks for sending aggregation again right away like some > Broadcom APs will. Yep, both TX and RX aggregation requests have to be denied. And this patch would be incomplete without handling this case. Will send a v2. Sujith