From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-ey0-f174.google.com ([209.85.215.174]:48673 "EHLO mail-ey0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754760Ab2APTWb (ORCPT ); Mon, 16 Jan 2012 14:22:31 -0500 Received: by eaac11 with SMTP id c11so314935eaa.19 for ; Mon, 16 Jan 2012 11:22:30 -0800 (PST) From: Helmut Schaa To: Johannes Berg Cc: linux-wireless@vger.kernel.org Subject: Re: Re: [RFC] mac80211: Fix possible race between sta_unblock and network softirq Date: Mon, 16 Jan 2012 20:22:21 +0100 Message-ID: <331689478.qzl2dPmWvj@helmutmobil.site> (sfid-20120116_202235_740425_527BDDCC) In-Reply-To: <1326732693.3510.21.camel@jlt3.sipsolutions.net> References: <1326728542-31697-1-git-send-email-helmut.schaa@googlemail.com> <1326732693.3510.21.camel@jlt3.sipsolutions.net> MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Sender: linux-wireless-owner@vger.kernel.org List-ID: Am Montag, 16. Januar 2012, 17:51:33 schrieb Johannes Berg: > On Mon, 2012-01-16 at 16:42 +0100, Helmut Schaa wrote: > > Signed-off-by: Helmut Schaa > > --- > > > > I'm currently writing some code for rt2800 that requires the driver > > to stop sending to a specific station for a short period of time > > (until all AMPDUs are finished to work around a hw issue that affects > > rate sampling with minstrel_ht). I decided to give > > ieee80211_sta_block_awake a try, however, the machine sometimes locked > > up while running some performance tests but due to a hw watchdog I > > wasn't able to get any sort of backtrace :( > > > > So, while doing some review of the ieee80211_sta_block_awake I came > > across this and wondered if softirqs should be disabled when delivering > > the buffered frames in sta_unblock. > > > > Using this patch I cannot reproduce the lockup anymore. > > > > So, is there any special reason this single code path in sta_unblock > > doesn't disable softirqs? > > This seems right The patch or the current approach without disable_bh? > -- not sure where the lockup would be though. Not sure either :( unfortunately I cannot disable the hw watchdog (and that has a timeout of only 2 seconds). Maybe I can reproduce it with a regular rt2800 PCI card ... Helmut