From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965288AbaH0XOK (ORCPT ); Wed, 27 Aug 2014 19:14:10 -0400 Received: from mail-bl2lp0211.outbound.protection.outlook.com ([207.46.163.211]:34123 "EHLO na01-bl2-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S965033AbaH0XOI convert rfc822-to-8bit (ORCPT ); Wed, 27 Aug 2014 19:14:08 -0400 From: KY Srinivasan To: Sitsofe Wheeler CC: Dexuan Cui , Greg Kroah-Hartman , Haiyang Zhang , "devel@linuxdriverproject.org" , "linux-kernel@vger.kernel.org" Subject: RE: [PANIC, hyperv] BUG: unable to handle kernel paging request at ffff880077800004 (hv_ringbuffer_write) Thread-Topic: [PANIC, hyperv] BUG: unable to handle kernel paging request at ffff880077800004 (hv_ringbuffer_write) Thread-Index: AQHPvFjYjJn6yhiZAUmfcA+tXSCe25vhYa6AgAA9PQCAARoEAIABlgcAgAANEQCAAAyZgIAAIPwAgAAi6gCAABhF8IAAVx2AgAABQrA= Date: Wed, 27 Aug 2014 23:13:47 +0000 Message-ID: References: <20140820092630.GA1478@sucs.org> <20140825174132.GA17681@sucs.org> <20140827104408.GC1827@sucs.org> <20140827121559.GA14286@sucs.org> <20140827161900.GA25326@sucs.org> <51ae44fcae424365a6d78f3597175d77@BY2PR0301MB0711.namprd03.prod.outlook.com> <20140827225739.GA24590@sucs.org> In-Reply-To: <20140827225739.GA24590@sucs.org> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [2001:4898:80e0:ee43::3] x-microsoft-antispam: BCL:0;PCL:0;RULEID:;UriScan:; x-forefront-prvs: 0316567485 x-forefront-antispam-report: SFV:NSPM;SFS:(6009001)(24454002)(51704005)(199003)(377454003)(189002)(13464003)(86612001)(87936001)(15395725005)(77982001)(15202345003)(79102001)(21056001)(101416001)(33646002)(106116001)(81342001)(92566001)(106356001)(105586002)(76176999)(85852003)(77096002)(81542001)(95666004)(76482001)(74316001)(99286002)(1411001)(54356999)(50986999)(15975445006)(83072002)(110136001)(99396002)(19580395003)(108616004)(74502001)(31966008)(74662001)(19580405001)(93886004)(4396001)(85306004)(83322001)(76576001)(80022001)(2656002)(90102001)(46102001)(107046002)(86362001)(64706001)(20776003)(7059011)(3826002)(24736002);DIR:OUT;SFP:;SCL:1;SRVR:BY2PR0301MB0711;H:BY2PR0301MB0711.namprd03.prod.outlook.com;FPR:;MLV:sfv;PTR:InfoNoRecords;A:1;MX:1;LANG:en; Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 X-OriginatorOrg: microsoft.onmicrosoft.com Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > -----Original Message----- > From: Sitsofe Wheeler [mailto:sitsofe@gmail.com] > Sent: Wednesday, August 27, 2014 3:58 PM > To: KY Srinivasan > Cc: Dexuan Cui; Greg Kroah-Hartman; Haiyang Zhang; > devel@linuxdriverproject.org; linux-kernel@vger.kernel.org > Subject: Re: [PANIC, hyperv] BUG: unable to handle kernel paging request at > ffff880077800004 (hv_ringbuffer_write) > > On Wed, Aug 27, 2014 at 06:45:55PM +0000, KY Srinivasan wrote: > > > > > -----Original Message----- > > > From: Sitsofe Wheeler [mailto:sitsofe@gmail.com] > > > Sent: Wednesday, August 27, 2014 9:19 AM > > > > > > > BTW, with the patch below, hyperv_fb can work now, BUT, > > > > *occasionally*, > > > > storvsc_probe() -> ... -> vmbus_open() -> can fail due to > > > > HV_STATUS_INVALID_ALIGNMENT... > > > > > > I applied your new patch on top of KY's pieces (it applied cleanly) > > > and while it doesn't blow up, one warning is printed out and the UP > > > boot seemed to stall after input: TPPS/2 message (but pressing > > > ctrl-alt-delete allows the system to reboot cleanly). > > > > First let me thank you guys for looking into this issue. Looking at > > your dmesg, it looked like storvsc probe failed as Dexuan had seen. > > Since the failure appears to be alignment related, perhaps we could > > test with allocating a page all the time (and getting rid of the > > kmalloc). Sitsofe, here is a patch based on Dexuan's patch. If this > > works, I will probably minimize failure cases by pre-allocating > > per-cpu pages for this.: > > After some modifications to apply on top of your previous patches applying > this latest patch has cured the issues surrounding hyperv_fb issues on boot. > The only issue seen on boot now is similar to > https://lkml.org/lkml/2014/8/19/227 ... That is good to hear. I was under the impression that this issue would be resolved with all the cleanup we have done. The last patch-set I posted earlier today has the fix for vmbus_open bug that Dexuan had identified. If you could try with the BUG_ON elimination patch-set I sent out earlier today with the fix in hv.c that I had sent that would be great. > > How come previous alignment efforts weren't working out? I have chosen to always allocate a page and so alignment won't be an issue. I want to eliminate failure in this path and so, I will most likely do a per-cpu pre-allocation of this buffer. Thank you very much for taking the time to help us debug these issues. Regards, K. Y > > -- > Sitsofe | http://sucs.org/~sits/