From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030326AbWBNATX (ORCPT ); Mon, 13 Feb 2006 19:19:23 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1030329AbWBNATW (ORCPT ); Mon, 13 Feb 2006 19:19:22 -0500 Received: from e32.co.us.ibm.com ([32.97.110.150]:8680 "EHLO e32.co.us.ibm.com") by vger.kernel.org with ESMTP id S1030326AbWBNATW (ORCPT ); Mon, 13 Feb 2006 19:19:22 -0500 Message-ID: <43F12207.9010507@watson.ibm.com> Date: Mon, 13 Feb 2006 19:19:19 -0500 From: Hubertus Franke User-Agent: Mozilla Thunderbird 1.0.2 (Windows/20050317) X-Accept-Language: en-us, en MIME-Version: 1.0 To: Linux Kernel Mailing List Subject: SMP BUG Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Folks the change introduced in 2.6.16-rc2 over 2.6.15 wrt to the SMP initialization are wrong. Please apply to unroll the change.. Here is the logic ... sched_init is called from start_kernel before the architecture specific function cpu_check_smp() is called which is done as part of rest_init(). On s390 this actually sets the cpu_possible_map, which is now used in sched_init through the for_each_cpu without properly being initialized. As a result bringing 2nd and subsequent cpu online breaks. This should be a quick fix, until this chicken and egg problem is solved otherwise. -- Hubertus --- kernel/sched.c.orig 2006-02-13 19:08:28.000000000 -0500 +++ kernel/sched.c 2006-02-13 19:09:08.000000000 -0500 @@ -6111,7 +6111,7 @@ void __init sched_init(void) runqueue_t *rq; int i, j, k; - for_each_cpu(i) { + for (i = 0; i < NR_CPUS; i++ ) { prio_array_t *array; rq = cpu_rq(i);