From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757229AbZBKAyN (ORCPT ); Tue, 10 Feb 2009 19:54:13 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757794AbZBKApk (ORCPT ); Tue, 10 Feb 2009 19:45:40 -0500 Received: from smtp-outbound-1.vmware.com ([65.115.85.69]:38471 "EHLO smtp-outbound-1.vmware.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758934AbZBKApi (ORCPT ); Tue, 10 Feb 2009 19:45:38 -0500 Subject: Re: [BUGFIX/x86] Fix initialization of wakeup_cpu. From: Alok Kataria Reply-To: akataria@vmware.com To: Yinghai Lu Cc: Ingo Molnar , the arch/x86 maintainers , LKML In-Reply-To: <49921C4F.9050601@kernel.org> References: <1234297715.24155.29.camel@alok-dev1> <86802c440902101303u2fe671b0xe811543d40e0cd9@mail.gmail.com> <1234303240.24155.36.camel@alok-dev1> <49921C4F.9050601@kernel.org> Content-Type: text/plain Organization: VMware INC. Date: Tue, 10 Feb 2009 16:45:37 -0800 Message-Id: <1234313137.30391.13.camel@alok-dev1> Mime-Version: 1.0 X-Mailer: Evolution 2.8.0 (2.8.0-40.el5_1.1) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2009-02-10 at 16:31 -0800, Yinghai Lu wrote: > > > >> 2. also will break 64 bit.... > > isn't the default_x86_quirks defined for 64 bit too ? > > > 64 bit doesn't have genapic_apic_probe() > > need to change that to > #ifdef CONFIG_X86_32 > genapic_apic_probe(); > #endif > Ok here it is. -- With refactoring of wake_cpu macros the 32bit code in tip doesn't execute generic_apic_probe if CONFIG_X86_32_NON_STANDARD is not set. Even on a x86 STANDARD cpu we need to execute the generic_apic_probe function, as we rely on this function to execute the update_genapic quirk which initilizes apic->wakeup_cpu. Failing to do so results in we making a call to a null function in do_boot_cpu. The stack trace without the patch goes like this. Booting processor 1 APIC 0x1 ip 0x6000 BUG: unable to handle kernel NULL pointer dereference at (null) IP: [<(null)>] (null) *pdpt = 0000000000839001 *pde = 0000000000c97067 *pte = 0000000000000163 Oops: 0000 [#1] SMP last sysfs file: Modules linked in: Pid: 1, comm: swapper Not tainted (2.6.29-rc4-tip #18) VMware Virtual Platform EIP: 0062:[<00000000>] EFLAGS: 00010293 CPU: 0 EIP is at 0x0 EAX: 00000001 EBX: 00006000 ECX: c077ed00 EDX: 00006000 ESI: 00000001 EDI: 00000001 EBP: ef04cf40 ESP: ef04cf1c DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 006a Process swapper (pid: 1, ti=ef04c000 task=ef050000 task.ti=ef04c000) Stack: c0644e52 00000000 ef04cf24 ef04cf24 c064468d c0886dc0 00000000 c0702aea ef055480 00000001 00000101 dead4ead ffffffff ffffffff c08af530 00000000 c0709715 ef04cf60 ef04cf60 00000001 00000000 00000000 dead4ead ffffffff Call Trace: [] ? native_cpu_up+0x2de/0x45b [] ? do_fork_idle+0x0/0x19 [] ? _cpu_up+0x88/0xe8 [] ? cpu_up+0x42/0x4e [] ? kernel_init+0x99/0x14b [] ? kernel_init+0x0/0x14b [] ? kernel_thread_helper+0x7/0x10 Code: Bad EIP value. EIP: [<00000000>] 0x0 SS:ESP 006a:ef04cf1c I think we should call generic_apic_probe unconditionally for 32 bit now. Signed-off-by: Alok N Kataria Cc: Yinghai Lu Index: linux-tip-master/arch/x86/kernel/setup.c =================================================================== --- linux-tip-master.orig/arch/x86/kernel/setup.c 2009-02-10 12:05:18.000000000 -0800 +++ linux-tip-master/arch/x86/kernel/setup.c 2009-02-10 16:37:59.000000000 -0800 @@ -936,7 +936,7 @@ map_vsyscall(); #endif -#if defined(CONFIG_X86_32_NON_STANDARD) || defined(CONFIG_X86_BIGSMP) +#ifdef CONFIG_X86_32 generic_apic_probe(); #endif