From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751649AbcBHLfj (ORCPT ); Mon, 8 Feb 2016 06:35:39 -0500 Received: from e36.co.us.ibm.com ([32.97.110.154]:50852 "EHLO e36.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751348AbcBHLfh (ORCPT ); Mon, 8 Feb 2016 06:35:37 -0500 X-IBM-Helo: d03dlp03.boulder.ibm.com X-IBM-MailFrom: raghavendra.kt@linux.vnet.ibm.com X-IBM-RcptTo: linux-kernel@vger.kernel.org;linux-tip-commits@vger.kernel.org;stable@vger.kernel.org Message-ID: <56B87E32.4050003@linux.vnet.ibm.com> Date: Mon, 08 Feb 2016 17:08:26 +0530 From: Raghavendra K T Organization: IBM User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130625 Thunderbird/17.0.7 MIME-Version: 1.0 To: tglx@linutronix.de, mingo@kernel.org, linux-mm@kvack.org, mpe@ellerman.id.au, hpa@zytor.com, nikunj@linux.vnet.ibm.com, linuxppc-dev@lists.ozlabs.org, peterz@infradead.org, vdavydov@parallels.com, gkurz@linux.vnet.ibm.com, linux-kernel@vger.kernel.org, raghavendra.kt@linux.vnet.ibm.com, jstancek@redhat.com, benh@kernel.crashing.org, anton@samba.org, grant.likely@linaro.org, paulus@samba.org, Greg Kroah-Hartman , stable@vger.kernel.org CC: tip-bot for Raghavendra K T , linux-tip-commits@vger.kernel.org Subject: Re: [tip:sched/urgent] sched: Fix crash in sched_init_numa() References: <1452884483-11676-1-git-send-email-raghavendra.kt@linux.vnet.ibm.com> In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 16020811-0021-0000-0000-000016D75D64 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/19/2016 07:08 PM, tip-bot for Raghavendra K T wrote: > Commit-ID: 9c03ee147193645be4c186d3688232fa438c57c7 > Gitweb: http://git.kernel.org/tip/9c03ee147193645be4c186d3688232fa438c57c7 > Author: Raghavendra K T > AuthorDate: Sat, 16 Jan 2016 00:31:23 +0530 > Committer: Ingo Molnar > CommitDate: Tue, 19 Jan 2016 08:42:20 +0100 > > sched: Fix crash in sched_init_numa() > > The following PowerPC commit: > > c118baf80256 ("arch/powerpc/mm/numa.c: do not allocate bootmem memory for non existing nodes") > > avoids allocating bootmem memory for non existent nodes. > > But when DEBUG_PER_CPU_MAPS=y is enabled, my powerNV system failed to boot > because in sched_init_numa(), cpumask_or() operation was done on > unallocated nodes. > > Fix that by making cpumask_or() operation only on existing nodes. > > [ Tested with and w/o DEBUG_PER_CPU_MAPS=y on x86 and PowerPC. ] > > Reported-by: Jan Stancek > Tested-by: Jan Stancek > Signed-off-by: Raghavendra K T > Cc: > Cc: > Cc: > Cc: > Cc: > Cc: > Cc: > Cc: > Cc: > Cc: > Cc: > Link: http://lkml.kernel.org/r/1452884483-11676-1-git-send-email-raghavendra.kt@linux.vnet.ibm.com > Signed-off-by: Ingo Molnar > --- > kernel/sched/core.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/kernel/sched/core.c b/kernel/sched/core.c > index 44253ad..474658b 100644 > --- a/kernel/sched/core.c > +++ b/kernel/sched/core.c > @@ -6840,7 +6840,7 @@ static void sched_init_numa(void) > > sched_domains_numa_masks[i][j] = mask; > > - for (k = 0; k < nr_node_ids; k++) { > + for_each_node(k) { > if (node_distance(j, k) > sched_domains_numa_distance[i]) > continue; > > > > Hello Greg, Above commit fixes the debug kernel crash in 4.4 kernel [ when DEBUG_PER_CPU_MAPS=y to be precise]. This is a regression in 4.4 from 4.3 and should be ideally present in 4.4-stable. Could you please pull in this change.?