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=-12.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 47074C433E7 for ; Tue, 13 Oct 2020 14:01:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id ED7252479B for ; Tue, 13 Oct 2020 14:01:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388236AbgJMOBb (ORCPT ); Tue, 13 Oct 2020 10:01:31 -0400 Received: from foss.arm.com ([217.140.110.172]:60394 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726867AbgJMOBb (ORCPT ); Tue, 13 Oct 2020 10:01:31 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id D0D2231B; Tue, 13 Oct 2020 07:01:30 -0700 (PDT) Received: from e113632-lin.cambridge.arm.com (e113632-lin.cambridge.arm.com [10.1.194.46]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id AD83A3F66B; Tue, 13 Oct 2020 07:01:28 -0700 (PDT) From: Valentin Schneider To: linux-kernel@vger.kernel.org Cc: tglx@linutronix.de, mingo@kernel.org, bigeasy@linutronix.de, qais.yousef@arm.com, swood@redhat.com, peterz@infradead.org, valentin.schneider@arm.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, bristot@redhat.com, vincent.donnefort@arm.com, tj@kernel.org Subject: [PATCH 1/2] sched: Deny self-issued __set_cpus_allowed_ptr() when migrate_disable() Date: Tue, 13 Oct 2020 15:01:15 +0100 Message-Id: <20201013140116.26651-1-valentin.schneider@arm.com> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20201005145717.346020688@infradead.org> References: <20201005145717.346020688@infradead.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org migrate_disable(); set_cpus_allowed_ptr(current, {something excluding task_cpu(current)}); affine_move_task(); <-- never returns Signed-off-by: Valentin Schneider --- kernel/sched/core.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 4ccd1099adaa..7f4e38819de1 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -2189,6 +2189,11 @@ static int __set_cpus_allowed_ptr(struct task_struct *p, if (!(flags & SCA_MIGRATE_ENABLE) && cpumask_equal(&p->cpus_mask, new_mask)) goto out; + if (p == current && + is_migration_disabled(p) && + !cpumask_test_cpu(task_cpu(p), new_mask)) + ret = -EBUSY; + /* * Picking a ~random cpu helps in cases where we are changing affinity * for groups of tasks (ie. cpuset), so that load balancing is not -- 2.27.0