Return-path: Received: from 39.mail-out.ovh.net ([213.251.138.60]:57229 "HELO 39.mail-out.ovh.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1751304AbZA1MKL (ORCPT ); Wed, 28 Jan 2009 07:10:11 -0500 Date: Wed, 28 Jan 2009 13:12:37 +0100 From: Samuel Ortiz To: Tomas Winkler Cc: Jason Andryuk , reinette chatre , "linux-wireless@vger.kernel.org" Subject: Re: kernel BUG at drivers/net/wireless/iwlwifi/iwl3945-base.c:3127! Message-ID: <20090128121237.GB3197@sortiz.org> (sfid-20090128_131017_774697_FD013214) Reply-To: Samuel Ortiz References: <760481.57662.qm@web57614.mail.re1.yahoo.com> <20090126114453.GB3197@sortiz.org> <20090127162437.GA3596@sortiz.org> <1ba2fa240901272312j270eedb5x33534a9703d26e06@mail.gmail.com> <20090128113751.GA3197@sortiz.org> <1ba2fa240901280352o56ccbc07h50c7a4bfcd0ac9ab@mail.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <1ba2fa240901280352o56ccbc07h50c7a4bfcd0ac9ab@mail.gmail.com> Sender: linux-wireless-owner@vger.kernel.org List-ID: On Wed, Jan 28, 2009 at 01:52:17PM +0200, Tomas Winkler wrote: > On Wed, Jan 28, 2009 at 1:37 PM, Samuel Ortiz wrote: > > On Wed, Jan 28, 2009 at 09:12:48AM +0200, Tomas Winkler wrote: > >> On Wed, Jan 28, 2009 at 1:31 AM, Jason Andryuk wrote: > >> >> No, that's just a consequence of the bug, not the bug itself. > >> >> Would you mind applying this patch on top of your latest wireless-testing tree > >> >> and testing 3945 with it ? Thanks for your patience. > >> > > >> > The patch did not cleanly apply, but I just removed the lines > >> > indicated in the patch. It crashed with a NULL pointer dereference. > >> > >> Samuel > >> It was really wrong try, you cannot just leave place where firmware > >> updated read pointer unallocated. I would rather focus on differences > >> introduced by this patch. > > Well, that's what I did. I neglected to check if rb_stts were actually used. > > > > > >> commit 738910c064ff461051cd37e17199f270ff88a9a3 iwl3945: use rx queue > >> management infrastructure from iwlcore is the first to trigger the > >> BUG_ON. However, prior versions would dereference a NULL pointer > >> before the driver could get far enough to trigger the BUG_ON. > > I know, that's what Jason described. > > I think I now understand why. Prior to > > 738910c064ff461051cd37e17199f270ff88a9a3, you introduced > > c2a0aa3cb733452e749727680e380dca6cc10a68 without actually allocating the > > rb_stts pointer, which was really wrong too. > > Yes I made mistake then I tought that 3945 take also init path of agn > already... Now it's hard to besect :(. > I suspect the rx queue managment infrastructure more because we brohgt > iwlagn bug into 3945 I guess it wrong rx buffer index handling. It's > really important we nail it now this will solve also our troubles in > iwlagn, where it get lost upon tons of patches. I agree. I also suspect that a lot more people will report the same problem when this code leaves wireless-testing for upstream inclusion. Cheers, Samuel. > Thanks > Tomas -- Intel Open Source Technology Centre http://oss.intel.com/