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=-19.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,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 DB07FC47083 for ; Wed, 2 Jun 2021 16:48:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C9D98610A1 for ; Wed, 2 Jun 2021 16:48:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231158AbhFBQts (ORCPT ); Wed, 2 Jun 2021 12:49:48 -0400 Received: from mail.kernel.org ([198.145.29.99]:33006 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230109AbhFBQtp (ORCPT ); Wed, 2 Jun 2021 12:49:45 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 60D4560FF0; Wed, 2 Jun 2021 16:47:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1622652482; bh=E3TlMrPTXQ5XHtnrLFnCnJBvZrG0Ks1d7FMKjXZekd4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ca5xjCaOLZHAyMZvGeW56tIZ7IeONKRLOl1sEt6dKh5VPfEKBJSMZ1fE7CAc8pPYE MBtv+BmseI1M14/3/MhDnvkqjqXuJaCux4H/KdyJZ47opYqkPXctVILs/p1nAQmVF9 iLTJZrHN/CrKAbcv/CyTM4i8nSR0s5/139DsMYX8PltVPDUG3NjoqkXb7wJSZF77k3 0Bk+Y+cq6LobJ06ewq6fb5lFRhITiCU9ZJeQLR1AxC4au3tc9rbJw77vycGQXoIfeM aiodNB+vpyjfG17mHpy0GN6czkb2jqlYpP/zO9j4qitLYEZhSW8KJZRIsgZV8CxHKr KrrAuzmoMjfzA== From: Will Deacon To: linux-arm-kernel@lists.infradead.org Cc: linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, Will Deacon , Catalin Marinas , Marc Zyngier , Greg Kroah-Hartman , Peter Zijlstra , Morten Rasmussen , Qais Yousef , Suren Baghdasaryan , Quentin Perret , Tejun Heo , Johannes Weiner , Ingo Molnar , Juri Lelli , Vincent Guittot , "Rafael J. Wysocki" , Dietmar Eggemann , Daniel Bristot de Oliveira , Valentin Schneider , kernel-team@android.com Subject: [PATCH v8 08/19] sched: Reject CPU affinity changes based on task_cpu_possible_mask() Date: Wed, 2 Jun 2021 17:47:08 +0100 Message-Id: <20210602164719.31777-9-will@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20210602164719.31777-1-will@kernel.org> References: <20210602164719.31777-1-will@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-arch@vger.kernel.org Reject explicit requests to change the affinity mask of a task via set_cpus_allowed_ptr() if the requested mask is not a subset of the mask returned by task_cpu_possible_mask(). This ensures that the 'cpus_mask' for a given task cannot contain CPUs which are incapable of executing it, except in cases where the affinity is forced. Reviewed-by: Quentin Perret Signed-off-by: Will Deacon --- kernel/sched/core.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 0c1b6f1a6c91..b23c7f0ab31a 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -2347,15 +2347,17 @@ static int __set_cpus_allowed_ptr(struct task_struct *p, u32 flags) { const struct cpumask *cpu_valid_mask = cpu_active_mask; + const struct cpumask *cpu_allowed_mask = task_cpu_possible_mask(p); unsigned int dest_cpu; struct rq_flags rf; struct rq *rq; int ret = 0; + bool kthread = p->flags & PF_KTHREAD; rq = task_rq_lock(p, &rf); update_rq_clock(rq); - if (p->flags & PF_KTHREAD || is_migration_disabled(p)) { + if (kthread || is_migration_disabled(p)) { /* * Kernel threads are allowed on online && !active CPUs, * however, during cpu-hot-unplug, even these might get pushed @@ -2369,6 +2371,11 @@ static int __set_cpus_allowed_ptr(struct task_struct *p, cpu_valid_mask = cpu_online_mask; } + if (!kthread && !cpumask_subset(new_mask, cpu_allowed_mask)) { + ret = -EINVAL; + goto out; + } + /* * Must re-check here, to close a race against __kthread_bind(), * sched_setaffinity() is not guaranteed to observe the flag. -- 2.32.0.rc0.204.g9fa02ecfa5-goog