Return-path: Received: from mail.candelatech.com ([208.74.158.172]:48503 "EHLO ns3.lanforge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752110Ab0LHPlE (ORCPT ); Wed, 8 Dec 2010 10:41:04 -0500 Message-ID: <4CFFA70A.2050307@candelatech.com> Date: Wed, 08 Dec 2010 07:40:58 -0800 From: Ben Greear MIME-Version: 1.0 To: Vasanthakumar Thiagarajan CC: Vasanth Thiagarajan , "Luis R. Rodriguez" , "greearb@gmail.com" , "linux-wireless@vger.kernel.org" , "ath9k-devel@venema.h4ckr.net" Subject: Re: [PATCH] ath9k: Check for NULL sta in ath_tx_start References: <1291698829-22765-1-git-send-email-greearb@candelatech.com> <4CFDC7D8.3080100@candelatech.com> <20101207074237.GA2179@vasanth-laptop> <4CFDE702.3020301@candelatech.com> <20101207083147.GA19720@vasanth-laptop> <4CFE6B42.8000806@candelatech.com> <20101208051745.GA24465@vasanth-laptop> In-Reply-To: <20101208051745.GA24465@vasanth-laptop> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Sender: linux-wireless-owner@vger.kernel.org List-ID: On 12/07/2010 09:17 PM, Vasanthakumar Thiagarajan wrote: > On Tue, Dec 07, 2010 at 10:43:38PM +0530, Ben Greear wrote: >> On 12/07/2010 12:31 AM, Vasanthakumar Thiagarajan wrote: >>> On Tue, Dec 07, 2010 at 01:19:22PM +0530, Ben Greear wrote: >>>> On 12/06/2010 11:42 PM, Vasanthakumar Thiagarajan wrote: >>>>> On Tue, Dec 07, 2010 at 11:06:24AM +0530, Ben Greear wrote: >>>>>> On 12/06/2010 09:21 PM, Luis R. Rodriguez wrote: >>>>>>> On Mon, Dec 6, 2010 at 9:13 PM, wrote: >>>>>>>> From: Ben Greear >>>>>>>> >>>>>>>> It can be NULL according to docs, and logging showed it >>>>>>>> to be NULL in practice. >>>>>>>> >>>>>>>> Signed-off-by: Ben Greear >>>>>>> >>>>>>> Does this fix an oops? If so can you explain and provide the trace and >>>>>>> resubmit and cc stable in the commit log? >>>>>> >>>>>> I think it fixes the TID corruption I posted about earlier. It seems >>>>>> so obvious though, that I'm curious why no one else sees problems, >>>>>> and why I didn't see more crashes in my setup. >>>>>> >>>>>> (The paprd code appears to send with null STA, for instance, and my >>>>>> printks showed lots of NULL stas in my 16-sta test setup, though I >>>>>> don't think I'm using the paprd code path.) >>>>> >>>>> paprd is used only with>= AR9003. >>>> >>>> Whoever coded it up hopefully had that hardware...so why didn't >>>> they see lots of crashes? >>> >>> I myself tested it lot of times, but did not see any crash, weird. >> >> Looks like the offending change when in recently (11/4/10, one of Felix's >> patches). >> >> That is probably why no one else is hitting this yet, and it >> isn't needed for stable I'm guessing.... > > Nice, care to send a patch?. Yeah, it is not needed for stable. The same patch I originally posted to to start this thread should do just fine. If someone really wants an oops report, I can add an artificial BUG_ON to catch this, but for whatever reason, it normally just crashes things weirdly and perhaps sometimes screwed up the file-system, so I'd rather just have the patch go in as it is..I think it is obviously more correct than the existing code. Thanks, Ben > > Vasanth -- Ben Greear Candela Technologies Inc http://www.candelatech.com