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=-3.5 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED autolearn=no 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 94A57C433E0 for ; Mon, 15 Jun 2020 13:18:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6EB9E2074D for ; Mon, 15 Jun 2020 13:18:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="EkOga70b" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730358AbgFONSg (ORCPT ); Mon, 15 Jun 2020 09:18:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55132 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730182AbgFONSc (ORCPT ); Mon, 15 Jun 2020 09:18:32 -0400 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:e::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 940A7C061A0E for ; Mon, 15 Jun 2020 06:18:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=Content-Type:MIME-Version:References: Subject:Cc:To:From:Date:Message-ID:Sender:Reply-To:Content-Transfer-Encoding: Content-ID:Content-Description:In-Reply-To; bh=9IS5WVJ2phjtEPTaOLlk10bfugsOLl/vZKy3zNyERqY=; b=EkOga70bahOfJk9dvxQwccs31j Zk6NIUqUONGAhPlu/y2+e//vuqjvGZy8/H8lJG+bPS2nn2HqyQ/Y0XHOEJKMwdGUpS7OrhlH358Wf iKNlYCg7mop5FrOVqGYBvDvFzwYI3yHga1OdUkjB5NY1J2g4ZwF5OXtElNGx3KwPr/2FFojFsrTaH Wvnqc360isiZi4vxYEJGqbNZ9ih7wR0Y688A3s9+PndghP9CjN6FWcRWxUaN6aW8TXR6f6EZ1y7mH XnRX6RKjRzCRZgUnRWfJCSwZGESIqJnZEF3j1Cl8LkYy+l9MDl0aby0SEiez49iB4Ckl33e9sCJpr MF6WiWYw==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by bombadil.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1jkp0F-0003Xk-4j; Mon, 15 Jun 2020 13:18:19 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id B4E8F30604B; Mon, 15 Jun 2020 15:18:16 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 0) id 9F495203C3762; Mon, 15 Jun 2020 15:18:16 +0200 (CEST) Message-ID: <20200615131143.191539791@infradead.org> User-Agent: quilt/0.66 Date: Mon, 15 Jun 2020 14:56:56 +0200 From: Peter Zijlstra To: mingo@kernel.org, tglx@linutronix.de Cc: linux-kernel@vger.kernel.org, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, paulmck@kernel.org, frederic@kernel.org, peterz@infradead.org Subject: [PATCH 2/6] sched: Verify some SMP assumptions References: <20200615125654.678940605@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Validate that: - __smp_call_single_queue() is only used on remote CPUs - task and rq CPUs match on activate_task() (and always use activate_task() where we should) Signed-off-by: Peter Zijlstra (Intel) --- kernel/sched/core.c | 8 ++++---- kernel/smp.c | 2 ++ 2 files changed, 6 insertions(+), 4 deletions(-) --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -1311,6 +1311,8 @@ static inline void dequeue_task(struct r void activate_task(struct rq *rq, struct task_struct *p, int flags) { + SCHED_WARN_ON(task_cpu(p) != cpu_of(rq)); + if (task_contributes_to_load(p)) rq->nr_uninterruptible--; @@ -1474,8 +1476,7 @@ static struct rq *move_queued_task(struc { lockdep_assert_held(&rq->lock); - WRITE_ONCE(p->on_rq, TASK_ON_RQ_MIGRATING); - dequeue_task(rq, p, DEQUEUE_NOCLOCK); + deactivate_task(rq, p, DEQUEUE_NOCLOCK); set_task_cpu(p, new_cpu); rq_unlock(rq, rf); @@ -1483,8 +1484,7 @@ static struct rq *move_queued_task(struc rq_lock(rq, rf); BUG_ON(task_cpu(p) != new_cpu); - enqueue_task(rq, p, 0); - p->on_rq = TASK_ON_RQ_QUEUED; + activate_task(rq, p, 0); check_preempt_curr(rq, p, 0); return rq; --- a/kernel/smp.c +++ b/kernel/smp.c @@ -135,6 +135,8 @@ static DEFINE_PER_CPU_SHARED_ALIGNED(cal void __smp_call_single_queue(int cpu, struct llist_node *node) { + WARN_ON_ONCE(cpu == smp_processor_id()); + /* * The list addition should be visible before sending the IPI * handler locks the list to pull the entry off it because of