From patchwork Mon Sep 13 13:13:07 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 510467 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=-19.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT autolearn=ham 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 AAD3DC433F5 for ; Mon, 13 Sep 2021 14:30:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 93C7060F58 for ; Mon, 13 Sep 2021 14:30:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1343498AbhIMOb4 (ORCPT ); Mon, 13 Sep 2021 10:31:56 -0400 Received: from mail.kernel.org ([198.145.29.99]:52002 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1347105AbhIMOaO (ORCPT ); Mon, 13 Sep 2021 10:30:14 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id C2F6A61B80; Mon, 13 Sep 2021 13:51:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1631541070; bh=qEk3uD+l+IIHXcQHXoO4etyYJ0jv15YW+EmtSp2e+gU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=qSqoEinrUwWdqS7VnmgHSMlIyMGABIxZiCHn6F2qo7gJua4NHaftOIlGR/StNGdam 63X9/0QKzFiPipW3TE/8n1SWc4zzmPr2IcJf1wqkVWz+N4Jq0B7n7SVwf0VE5vIPXj R3fFCaxMovF/EqnZmBluJGP+JvT+nWrNq6J+e9Dk= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Waiman Long , Tejun Heo , Sasha Levin Subject: [PATCH 5.14 133/334] cgroup/cpuset: Fix a partition bug with hotplug Date: Mon, 13 Sep 2021 15:13:07 +0200 Message-Id: <20210913131117.866146421@linuxfoundation.org> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20210913131113.390368911@linuxfoundation.org> References: <20210913131113.390368911@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Waiman Long [ Upstream commit 15d428e6fe77fffc3f4fff923336036f5496ef17 ] In cpuset_hotplug_workfn(), the detection of whether the cpu list has been changed is done by comparing the effective cpus of the top cpuset with the cpu_active_mask. However, in the rare case that just all the CPUs in the subparts_cpus are offlined, the detection fails and the partition states are not updated correctly. Fix it by forcing the cpus_updated flag to true in this particular case. Fixes: 4b842da276a8 ("cpuset: Make CPU hotplug work with partition") Signed-off-by: Waiman Long Signed-off-by: Tejun Heo Signed-off-by: Sasha Levin --- kernel/cgroup/cpuset.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index adb5190c4429..592e9e37542f 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -3168,6 +3168,13 @@ static void cpuset_hotplug_workfn(struct work_struct *work) cpus_updated = !cpumask_equal(top_cpuset.effective_cpus, &new_cpus); mems_updated = !nodes_equal(top_cpuset.effective_mems, new_mems); + /* + * In the rare case that hotplug removes all the cpus in subparts_cpus, + * we assumed that cpus are updated. + */ + if (!cpus_updated && top_cpuset.nr_subparts_cpus) + cpus_updated = true; + /* synchronize cpus_allowed to cpu_active_mask */ if (cpus_updated) { spin_lock_irq(&callback_lock);