From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 25D7AC4CECD for ; Tue, 17 Sep 2019 14:57:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0731221897 for ; Tue, 17 Sep 2019 14:57:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728815AbfIQO5h (ORCPT ); Tue, 17 Sep 2019 10:57:37 -0400 Received: from Galois.linutronix.de ([193.142.43.55]:42147 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728722AbfIQO5h (ORCPT ); Tue, 17 Sep 2019 10:57:37 -0400 Received: from bigeasy by Galois.linutronix.de with local (Exim 4.80) (envelope-from ) id 1iAEv4-0000D2-0Y; Tue, 17 Sep 2019 16:57:30 +0200 Date: Tue, 17 Sep 2019 16:57:29 +0200 From: Sebastian Andrzej Siewior To: Scott Wood Cc: Thomas Gleixner , Steven Rostedt , Peter Zijlstra , Juri Lelli , Daniel Bristot de Oliveira , Clark Williams , linux-kernel@vger.kernel.org, linux-rt-users@vger.kernel.org Subject: Re: [PATCH RT 2/8] sched: __set_cpus_allowed_ptr: Check cpus_mask, not cpus_ptr Message-ID: <20190917145729.pul3dmbrdnshne6m@linutronix.de> References: <20190727055638.20443-1-swood@redhat.com> <20190727055638.20443-3-swood@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20190727055638.20443-3-swood@redhat.com> User-Agent: NeoMutt/20180716 Sender: linux-rt-users-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-rt-users@vger.kernel.org On 2019-07-27 00:56:32 [-0500], Scott Wood wrote: > This function is concerned with the long-term cpu mask, not the > transitory mask the task might have while migrate disabled. Before > this patch, if a task was migrate disabled at the time > __set_cpus_allowed_ptr() was called, and the new mask happened to be > equal to the cpu that the task was running on, then the mask update > would be lost. lost as in "would not be carried out" I assume. > Signed-off-by: Scott Wood > --- > 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 c3407707e367..6e643d656d71 100644 > --- a/kernel/sched/core.c > +++ b/kernel/sched/core.c > @@ -1218,7 +1218,7 @@ static int __set_cpus_allowed_ptr(struct task_struct *p, > goto out; > } > > - if (cpumask_equal(p->cpus_ptr, new_mask)) > + if (cpumask_equal(&p->cpus_mask, new_mask)) > goto out; > > if (!cpumask_intersects(new_mask, cpu_valid_mask)) { Sebastian