Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753726AbZFISbP (ORCPT ); Tue, 9 Jun 2009 14:31:15 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751654AbZFISa7 (ORCPT ); Tue, 9 Jun 2009 14:30:59 -0400 Received: from mx2.redhat.com ([66.187.237.31]:34350 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752428AbZFISa6 (ORCPT ); Tue, 9 Jun 2009 14:30:58 -0400 Message-ID: <4A2EAA53.7060006@redhat.com> Date: Tue, 09 Jun 2009 21:30:43 +0300 From: Avi Kivity User-Agent: Thunderbird 2.0.0.21 (X11/20090320) MIME-Version: 1.0 To: Dan Williams CC: Stephen Hemminger , Rusty Russell , "Rafael J. Wysocki" , Linux Kernel Mailing List , Kernel Testers List Subject: Re: [Bug #13116] Can't boot with nosmp References: <20090608091544.53a94235@nehalam> <20090608170437.1c2386a5@nehalam> In-Reply-To: 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 Content-Length: 1602 Lines: 44 Dan Williams wrote: > On Mon, Jun 8, 2009 at 5:04 PM, Stephen Hemminger wrote: > >> I did some more debugging, and the problem appears to be that >> booting with nosmp still leaves all the CPU's present in the cpu >> possible mask. So code like dma engine (or loopback device), that >> use alloc_percpu get broken. >> >> Not sure why all the cpu's are still showing up in the possible mask. >> Rusty? do you have an answer. >> > > Would this recent commit also fix this issue? > > commit a4c0364be3f43d3e17fe19270f8b3d64881606e6 > Author: Avi Kivity > Date: Sat Jun 6 12:34:39 2009 +0300 > > KVM: Explicity initialize cpus_hardware_enabled > > Under CONFIG_MAXSMP, cpus_hardware_enabled is allocated from the heap and > not statically initialized. This causes a crash on reboot when kvm thinks > vmx is enabled on random nonexistent cpus and accesses nonexistent percpu > lists. > > Fix by explicitly clearing the variable. > > Cc: stable@kernel.org > Reported-and-tested-by: Yinghai Lu > Signed-off-by: Avi Kivity > This only affects reboots. But yes, the cpumask code has bugs. Does the .config involved select MAXSMP? -- I have a truly marvellous patch that fixes the bug which this signature is too narrow to contain. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/