Return-path: Received: from he.sipsolutions.net ([78.46.109.217]:35125 "EHLO sipsolutions.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751013Ab1K1NSO (ORCPT ); Mon, 28 Nov 2011 08:18:14 -0500 Subject: Re: [PATCH v3] mac80211: fix race condition caused by late addBA response From: Johannes Berg To: Emmanuel Grumbach Cc: Nikolay Martynov , linville@tuxdriver.com, linux-wireless@vger.kernel.org, Norbert Preining , Emmanuel Grumbach In-Reply-To: (sfid-20111128_133506_902028_2F8CE6CE) References: <1322378621-14647-1-git-send-email-mar.kolya@gmail.com> <1322378621-14647-2-git-send-email-mar.kolya@gmail.com> <1322394638.4044.32.camel@jlt3.sipsolutions.net> <1322394800.4044.33.camel@jlt3.sipsolutions.net> <1322412918.4044.37.camel@jlt3.sipsolutions.net> <1322468173.4060.0.camel@jlt3.sipsolutions.net> (sfid-20111128_133506_902028_2F8CE6CE) Content-Type: text/plain; charset="UTF-8" Date: Mon, 28 Nov 2011 14:18:05 +0100 Message-ID: <1322486285.4060.5.camel@jlt3.sipsolutions.net> (sfid-20111128_141817_248867_A970EFE3) Mime-Version: 1.0 Sender: linux-wireless-owner@vger.kernel.org List-ID: On Mon, 2011-11-28 at 14:34 +0200, Emmanuel Grumbach wrote: > On Mon, Nov 28, 2011 at 10:16, Johannes Berg wrote: > > On Mon, 2011-11-28 at 08:35 +0200, Emmanuel Grumbach wrote: > > > >> > /* > >> > * addba_resp_timer may have fired before we got here, and > >> > * caused WANT_STOP to be set. If the stop then was already > >> > * processed further, STOPPING might be set. > >> > */ > >> > > >> > > >> > Did you notice that I moved this code to after the dialog token check? > >> > > >> > >> Don't you think we should also send a delBA ? The AP thinks we will Tx > >> in Agg and basically we are now out of sync. > > > > We do, during the timer stop path, afaict. > > > > Yes, but obviously the AP didn't hear it since it sent the addBA resp. > IMHO, we should send it again. I don't think so? This is addressing a race between the timer & receiving the frame, so typically the delBA would not have gone out yet. johannes