From patchwork Fri Mar 17 15:15:05 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Waiman Long X-Patchwork-Id: 13179199 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E3A0BC74A5B for ; Fri, 17 Mar 2023 15:16:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231735AbjCQPQi (ORCPT ); Fri, 17 Mar 2023 11:16:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44170 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230232AbjCQPQf (ORCPT ); Fri, 17 Mar 2023 11:16:35 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4C0FA6FFCE for ; Fri, 17 Mar 2023 08:15:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1679066135; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=yyPOMwQLISxSVk5Hax7mBc5lUymcLlOh64gwiaoZAvQ=; b=RhCycSMZxz/FIotAeZK1ieNaAMnoyfyVzSSJtKsaa6q5PvSJaENzlrqfaEePZC/QtoHRWO pYpdcAvsITSNidw5l9waM2rBsjNDTwY0MYMKSPBbO+37sqsExjxnA2rCEu6EE+0Z4GVg16 Y3REEM6YvtgER94hDol24LHxMtxN9Ow= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-512-dZAI30q9PRKOvWTgzcfh4g-1; Fri, 17 Mar 2023 11:15:30 -0400 X-MC-Unique: dZAI30q9PRKOvWTgzcfh4g-1 Received: from smtp.corp.redhat.com (int-mx09.intmail.prod.int.rdu2.redhat.com [10.11.54.9]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 0602810146E3; Fri, 17 Mar 2023 15:15:30 +0000 (UTC) Received: from llong.com (unknown [10.22.10.238]) by smtp.corp.redhat.com (Postfix) with ESMTP id 83C49492B00; Fri, 17 Mar 2023 15:15:29 +0000 (UTC) From: Waiman Long To: Tejun Heo , Zefan Li , Johannes Weiner , Shuah Khan Cc: cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, Will Deacon , Peter Zijlstra , =?utf-8?q?Michal_Koutn=C3=BD?= , Juri Lelli , Waiman Long Subject: [PATCH v2 1/4] cgroup/cpuset: Fix partition root's cpuset.cpus update bug Date: Fri, 17 Mar 2023 11:15:05 -0400 Message-Id: <20230317151508.1225282-2-longman@redhat.com> In-Reply-To: <20230317151508.1225282-1-longman@redhat.com> References: <20230317151508.1225282-1-longman@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.9 Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org It was found that commit 7a2127e66a00 ("cpuset: Call set_cpus_allowed_ptr() with appropriate mask for task") introduced a bug that corrupted "cpuset.cpus" of a partition root when it was updated. It is because the tmp->new_cpus field of the passed tmp parameter of update_parent_subparts_cpumask() should not be used at all as it contains important cpumask data that should not be overwritten. Fix it by using tmp->addmask instead. Also update update_cpumask() to make sure that trialcs->cpu_allowed will not be corrupted until it is no longer needed. Fixes: 7a2127e66a00 ("cpuset: Call set_cpus_allowed_ptr() with appropriate mask for task") Signed-off-by: Waiman Long --- kernel/cgroup/cpuset.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index 636f1c682ac0..f310915d1257 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -1513,7 +1513,7 @@ static int update_parent_subparts_cpumask(struct cpuset *cs, int cmd, spin_unlock_irq(&callback_lock); if (adding || deleting) - update_tasks_cpumask(parent, tmp->new_cpus); + update_tasks_cpumask(parent, tmp->addmask); /* * Set or clear CS_SCHED_LOAD_BALANCE when partcmd_update, if necessary. @@ -1770,10 +1770,13 @@ static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs, /* * Use the cpumasks in trialcs for tmpmasks when they are pointers * to allocated cpumasks. + * + * Note that update_parent_subparts_cpumask() uses only addmask & + * delmask, but not new_cpus. */ tmp.addmask = trialcs->subparts_cpus; tmp.delmask = trialcs->effective_cpus; - tmp.new_cpus = trialcs->cpus_allowed; + tmp.new_cpus = NULL; #endif retval = validate_change(cs, trialcs); @@ -1838,6 +1841,11 @@ static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs, } spin_unlock_irq(&callback_lock); +#ifdef CONFIG_CPUMASK_OFFSTACK + /* Now trialcs->cpus_allowed is available */ + tmp.new_cpus = trialcs->cpus_allowed; +#endif + /* effective_cpus will be updated here */ update_cpumasks_hier(cs, &tmp, false);