From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from youngberry.canonical.com ([91.189.89.112]:55973 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752677Ab3ABNul (ORCPT ); Wed, 2 Jan 2013 08:50:41 -0500 Date: Wed, 2 Jan 2013 07:50:31 -0600 From: Seth Forshee To: Arend van Spriel Cc: Linus Torvalds , Brett Rudley , "Franky (Zhenhui) Lin" , Hante Meuleman , "John W. Linville" , Linux Wireless List , brcm80211-dev-list@broadcom.com Subject: Re: WARNING: at drivers/net/wireless/brcm80211/brcmsmac/main.c:7539 Message-ID: <20130102135031.GA11439@thinkpad-t410> (sfid-20130102_145045_076356_9EFFBF9C) References: <50E4229D.5000900@broadcom.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <50E4229D.5000900@broadcom.com> Sender: linux-wireless-owner@vger.kernel.org List-ID: On Wed, Jan 02, 2013 at 01:05:49PM +0100, Arend van Spriel wrote: > On 12/28/2012 07:07 AM, Linus Torvalds wrote: > > Ok, maybe somebody is interested in this.. I don't know what triggered > > it, but maybe the few lines around it give some clue. > > Hi Linus, > > I am interested (being paid for it kinda helps). The warning itself does > not necessarily have to be a problem, but the frameid mismatch between > tx status info and the related buffer taken from the DMA ring does. > Smells like a race condition, but I need to investigate that. > > > I think it's new to 3.8-rc1, because I haven't seen it before (well, > > I'm running current -git - v3.8.0-rc1-00035-g101e5c7470eb to be exact > > - but the networking changes since -rc1 are small and seem unrelated). > > But maybe it just happens under certain circumstances. > > We had a big contribution from Canonical (cc-ed Seth) in brcmsmac > itself. Not playing the blame game, but I suspect it has altered > circumstances making the real issue (that was already there) more likely > to happen. Hope that helps us nailing it down. I'm certain that both problems existed prior to 3.8-rc1. The warning itself has generated a fairly consistent trickle of bug reports for a while now. I haven't noticed any increased frequency of these messages; if anything I'd say I'm hitting the WARN_ON less often (though I've been doing a lot of testing under heavy load so my observations may not be typical). The channel mismatch errors are something I plan to look into, but I've been distracted by some background scanning problems (not specific to brcmsmac). Seth