From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759979AbXFDSMw (ORCPT ); Mon, 4 Jun 2007 14:12:52 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755934AbXFDSMo (ORCPT ); Mon, 4 Jun 2007 14:12:44 -0400 Received: from mx2.suse.de ([195.135.220.15]:38159 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754416AbXFDSMn (ORCPT ); Mon, 4 Jun 2007 14:12:43 -0400 From: Andi Kleen To: Andrew Morton Subject: Re: lguest rebroken in 2.6.22-rc3-mm1 Date: Mon, 4 Jun 2007 20:12:15 +0200 User-Agent: KMail/1.9.1 Cc: Matt Mackall , Rusty Russell , linux-kernel@vger.kernel.org References: <20070522223828.GV11115@waste.org> <20070604171932.GE11115@waste.org> <20070604102820.a4a0ee15.akpm@linux-foundation.org> In-Reply-To: <20070604102820.a4a0ee15.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200706042012.15915.ak@suse.de> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org > > > > Looks like this one got lost in rc3-mm1. > > Andi said that he fixed the zero-divide by other means? I determined it cannot happen in my source tree. When notsc is passed TSC CPUID is cleared and sched-clock works. I suspect what happens is that lguest forgets to clear the TSC cpuid bit when it disables TSC. Then the TSC frequency doesn't get computed and sched-clock can divide by zero.That's purely a lguest bug that needs to be fixed in lguest with a clear_bit(X86_FEATURE_TSC, &boot_cpu_data.x86_capability) somewhere -Andi