From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751804AbeEQMgm (ORCPT ); Thu, 17 May 2018 08:36:42 -0400 Received: from Galois.linutronix.de ([146.0.238.70]:46032 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750779AbeEQMgl (ORCPT ); Thu, 17 May 2018 08:36:41 -0400 Date: Thu, 17 May 2018 14:36:39 +0200 (CEST) From: Thomas Gleixner To: Rick Warner cc: Linux Kernel Mailing List Subject: Re: [bisected] rcu_sched detected stalls - 4.15 or newer kernel with some Xeon skylake CPUs and extended APIC In-Reply-To: Message-ID: References: <831e8a53-05d1-edfb-6287-fecfba22b8bd@microway.com> User-Agent: Alpine 2.21 (DEB 202 2017-01-01) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Rick, On Wed, 16 May 2018, Rick Warner wrote: > I've attached the dmesg output with the kernel parameter and supplied patch. Thanks for providing the data. I think I know what's wrong here. Does the patch below fix your problem? While you test, I go looking for a big brown paperbag. Thanks, tglx 8<---------------- --- a/arch/x86/kernel/apic/x2apic_cluster.c +++ b/arch/x86/kernel/apic/x2apic_cluster.c @@ -124,6 +124,7 @@ static void init_x2apic_ldr(void) goto update; } cmsk = cluster_hotplug_mask; + cmsk->clusterid = cluster; cluster_hotplug_mask = NULL; update: this_cpu_write(cluster_masks, cmsk);