Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752448AbWCPRo5 (ORCPT ); Thu, 16 Mar 2006 12:44:57 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752447AbWCPRo5 (ORCPT ); Thu, 16 Mar 2006 12:44:57 -0500 Received: from e31.co.us.ibm.com ([32.97.110.149]:3812 "EHLO e31.co.us.ibm.com") by vger.kernel.org with ESMTP id S1752448AbWCPRo4 (ORCPT ); Thu, 16 Mar 2006 12:44:56 -0500 Date: Thu, 16 Mar 2006 23:14:47 +0530 From: Srivatsa Vaddagiri To: Andrew Morton , torvalds@osdl.org Cc: linux-kernel@vger.kernel.org, shaohua.li@intel.com, bryce@osdl.org Subject: [PATCH] Check for online cpus before bringing them up Message-ID: <20060316174447.GA8184@in.ibm.com> Reply-To: vatsa@in.ibm.com Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.11 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1314 Lines: 48 Bryce reported a bug wherein offlining CPU0 (on x86 box) and then subsequently onlining it resulted in a lockup. On x86, CPU0 is never offlined. The subsequent attempt to online CPU0 doesn't take that into account. It actually tries to bootup the already booted CPU. Following patch fixes the problem (as acknowledged by Bryce). Please consider for inclusion in 2.6.16. Check if cpu is already online. Signed-off-by : Srivatsa Vaddagiri - arch/i386/kernel/smpboot.c | 6 ++++++ 1 files changed, 6 insertions(+) diff -puN arch/i386/kernel/smpboot.c~cpuhp arch/i386/kernel/smpboot.c --- linux-2.6.16-rc5/arch/i386/kernel/smpboot.c~cpuhp 2006-03-14 14:42:26.000000000 +0530 +++ linux-2.6.16-rc5-root/arch/i386/kernel/smpboot.c 2006-03-14 14:43:21.000000000 +0530 @@ -1029,6 +1029,12 @@ int __devinit smp_prepare_cpu(int cpu) int apicid, ret; lock_cpu_hotplug(); + + if (cpu_online(cpu)) { + ret = -EINVAL; + goto exit; + } + apicid = x86_cpu_to_apicid[cpu]; if (apicid == BAD_APICID) { ret = -ENODEV; _ -- Regards, vatsa - 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/