From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753733AbYLDMCh (ORCPT ); Thu, 4 Dec 2008 07:02:37 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750845AbYLDMC2 (ORCPT ); Thu, 4 Dec 2008 07:02:28 -0500 Received: from mga14.intel.com ([143.182.124.37]:6312 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750811AbYLDMC1 (ORCPT ); Thu, 4 Dec 2008 07:02:27 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.33,715,1220252400"; d="scan'208";a="86406801" Date: Thu, 4 Dec 2008 20:02:14 +0800 From: Wu Fengguang To: Andi Kleen Cc: LKML , Ingo Molnar , Andrew Morton , Jack Steiner , Yinghai Lu Subject: Re: 2.6.28-rc6: early panic with boot option "nosmp" Message-ID: <20081204120214.GA30833@localhost> References: <20081204022806.GA29293@localhost> <20081204101343.GO6703@one.firstfloor.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20081204101343.GO6703@one.firstfloor.org> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Dec 04, 2008 at 12:13:43PM +0200, Andi Kleen wrote: > On Thu, Dec 04, 2008 at 10:28:06AM +0800, Wu Fengguang wrote: > > Hi, > > > > The boot option "maxcpus=0" or "nosmp" makes kernel 2.6.28-rc6 panic > > immediately after booting: > > > > PANIC: early exception 0e rip 10:ffffffff8176d6ff error 0 cr2 9 > > It would be useful if you could look the ffffffff8176d6ff > address up in your System.map or using gdb. addr2line -e vmlinux -f 0xffffffff8176d6ff __get_smp_config /cc/linux-2.6/arch/x86/kernel/mpparse.c:607 582 /* 583 * Scan the memory blocks for an SMP configuration block. 584 */ 585 static void __init __get_smp_config(unsigned int early) 586 { 587 struct intel_mp_floating *mpf = mpf_found; 588 589 if (x86_quirks->mach_get_smp_config) { 590 if (x86_quirks->mach_get_smp_config(early)) 591 return; 592 } 593 if (acpi_lapic && early) 594 return; 595 /* 596 * ACPI supports both logical (e.g. Hyper-Threading) and physical 597 * processors, where MPS only supports physical. 598 */ 599 if (acpi_lapic && acpi_ioapic) { 600 printk(KERN_INFO "Using ACPI (MADT) for SMP configuration " 601 "information\n"); 602 return; 603 } else if (acpi_lapic) 604 printk(KERN_INFO "Using ACPI for processor (LAPIC) " 605 "configuration information\n"); 606 607 printk(KERN_INFO "Intel MultiProcessor Specification v1.%d\n", 608 mpf->mpf_specification); The exception raised on dereferencing mpf or mpf_found. Thanks, Fengguang