From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753353AbYIPIMH (ORCPT ); Tue, 16 Sep 2008 04:12:07 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752373AbYIPILw (ORCPT ); Tue, 16 Sep 2008 04:11:52 -0400 Received: from hobbit.corpit.ru ([81.13.33.150]:21026 "EHLO hobbit.corpit.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752257AbYIPILv (ORCPT ); Tue, 16 Sep 2008 04:11:51 -0400 Message-ID: <48CF6A45.3010204@msgid.tls.msk.ru> Date: Tue, 16 Sep 2008 12:11:49 +0400 From: Michael Tokarev Organization: Telecom Service, JSC User-Agent: Mozilla-Thunderbird 2.0.0.16 (X11/20080724) MIME-Version: 1.0 To: linux-kernel@vger.kernel.org Subject: PARAVIRT_GUEST bug? [was: Stable regression: usb-storage is stuck in 2.6.26.5] References: <20080913122143.4B13B908E@gandalf.tls.msk.ru> <48CBB626.4050300@msgid.tls.msk.ru> In-Reply-To: <48CBB626.4050300@msgid.tls.msk.ru> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Michael Tokarev wrote: [usb-storage hangs on asus M2NPV-VM (nVidia GeForce 6150/nForce 430) motherboard with latest bios] > Ok, it turned out to be pretty.. interesting. > > It's not a regression within -stable kernel series. The problem > happens when BOTH are true: > > - using latest BIOS for this mobo (1401), AND > - enabling KVM_GUEST in kernel. > > The only difference in my kernel config between .1 and .5 was > to enable KVM_GUEST and KVM_CLOCK, and also I2C_HELPER_AUTO > which was added by kernel update. > > Going with previous BIOS (1201) OR disabling PARAVIRT_GUEST > fixes the problem. I'll try to figure out which config > option is at problem here. After seeing similar situation on another motherboard, I become curious. Here's the result: M3A78-EM motherboard (also from Asus), AMD780G/SB700 etc. Updating to one of the latest bios makes the system unbootable. Kernel hangs on boot right after displaying SLUB: Genslabs=12, HWalign=64, Order=0-1, MinObjects=4, CPUs=2, Nodes=1 Reverting to the older BIOS or disabling PARAVIRT_GUEST in kernel fixes this (turning off KVM_GUEST isn't enough), and kernel happily boots further, with next line being hpet clockevent registered ... Reportedly, another Asus motherboard (M2N-SLI DELUXE) also hangs with new BIOS and KVM_GUEST optimizations turned on, but not on older BIOS. So it's quite.. funny. At least SOME latest BIOSes from Asustec, together with PARAVIRT_GUEST, -- a problem. Don't do either of those, and it's all ok. The question is if Asus introduced the same bug in quite.. some of their recent BIOSes, or PARAVIRT_GUEST code is somehow buggy and the bug is exposed by new BIOS code. Any hints on this? ;) Thanks! /mjt