From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932308AbYD2Szz (ORCPT ); Tue, 29 Apr 2008 14:55:55 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1764232AbYD2Sxc (ORCPT ); Tue, 29 Apr 2008 14:53:32 -0400 Received: from netops-testserver-3-out.sgi.com ([192.48.171.28]:41485 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1764215AbYD2Sxa (ORCPT ); Tue, 29 Apr 2008 14:53:30 -0400 Message-ID: <48176EA6.8060506@sgi.com> Date: Tue, 29 Apr 2008 11:53:26 -0700 From: Mike Travis User-Agent: Thunderbird 2.0.0.6 (X11/20070801) MIME-Version: 1.0 To: Ingo Molnar CC: Andrew Morton , Thomas Gleixner , "H. Peter Anvin" , linux-kernel@vger.kernel.org Subject: Re: [PATCH 0/1] x86: fix remove cpu_pda table patch References: <20080428210906.348866000@polaris-admin.engr.sgi.com> <20080428214541.GA16153@elte.hu> <48175CF8.4010105@sgi.com> In-Reply-To: <48175CF8.4010105@sgi.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Mike Travis wrote: > Ingo Molnar wrote: >> * Mike Travis wrote: >> >>> [Ingo - please replace "PATCH 07/11" with this one.] >>> >>> * Remove 544k bytes from the kernel by removing the boot_cpu_pda >>> array from the data section and allocating it during startup. >>> >>> Fixed panic in setup_per_cpu_areas when HOTPLUG_CPU not set. >>> >>> For inclusion into sched-devel/latest tree. >> sched-devel.git randconfig testing found another crash with your queue: >> >> [ 0.111060] Brought up 1 CPUs >> [ 0.111986] Total of 1 processors activated (4022.73 BogoMIPS). >> [ 0.112987] Testing NMI watchdog ... <1>BUG: unable to handle kernel NULL pointer dereference at 0000000000000040 >> [ 0.114982] IP: [] check_nmi_watchdog+0xb0/0x210 >> [ 0.114982] PGD 0 >> [ 0.114982] Oops: 0000 [1] SMP >> [ 0.114982] CPU 0 >> [............] >> >> http://redhat.com/~mingo/misc/config-Mon_Apr_28_23_25_25_CEST_2008.bad >> http://redhat.com/~mingo/misc/log-Mon_Apr_28_23_25_25_CEST_2008.bad >> >> Ingo > > Hi Ingo, > > I need a bit more information on your hardware configuration. Building a > kernel with the above config file started up fine on both the Intel and AMD > boxes. > > Based on the above output it looks like it might be a UP machine? ... Ok, I think I found it. In check_nmi_watchdog(): for (cpu = 0; cpu < NR_CPUS; cpu++) prev_nmi_count[cpu] = cpu_pda(cpu)->__nmi_count; As I mentioned it works fine on both of my systems so could you try it out? Thanks! Mike -- Subject: [PATCH 1/1] x86: change check_nmi_watchdog to use nr_cpu_ids * Change function check_nmi_watchdog() to use nr_cpu_ids instead of NR_CPUS. Based on: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6.git + sched-devel/latest .../mingo/linux-2.6-sched-devel.git Signed-off-by: Mike Travis --- arch/x86/kernel/nmi_64.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- linux-2.6.sched.orig/arch/x86/kernel/nmi_64.c +++ linux-2.6.sched/arch/x86/kernel/nmi_64.c @@ -88,7 +88,7 @@ int __init check_nmi_watchdog(void) if (!atomic_read(&nmi_active)) return 0; - prev_nmi_count = kmalloc(NR_CPUS * sizeof(int), GFP_KERNEL); + prev_nmi_count = kmalloc(nr_cpu_ids * sizeof(int), GFP_KERNEL); if (!prev_nmi_count) return -1; @@ -99,7 +99,7 @@ int __init check_nmi_watchdog(void) smp_call_function(nmi_cpu_busy, (void *)&endflag, 0, 0); #endif - for (cpu = 0; cpu < NR_CPUS; cpu++) + for (cpu = 0; cpu < nr_cpu_ids; cpu++) prev_nmi_count[cpu] = cpu_pda(cpu)->__nmi_count; local_irq_enable(); mdelay((20*1000)/nmi_hz); // wait 20 ticks