From patchwork Fri Oct 13 11:58:57 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Frederic Weisbecker X-Patchwork-Id: 152547 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a05:612c:2908:b0:403:3b70:6f57 with SMTP id ib8csp1835041vqb; Fri, 13 Oct 2023 05:00:39 -0700 (PDT) X-Google-Smtp-Source: AGHT+IGhWtps++tjuUUNPPeMn/ADLzs3TheIaBU90Yh7UzN//876l0VRUnsh+dqE/x62i0nkTkeP X-Received: by 2002:a05:6359:b9a:b0:14d:2dd5:a777 with SMTP id gf26-20020a0563590b9a00b0014d2dd5a777mr23096047rwb.2.1697198439070; Fri, 13 Oct 2023 05:00:39 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1697198439; cv=none; d=google.com; s=arc-20160816; b=b7WTgyCig+0bqAJHNSCp1fVrbEc90ddaLJTUbV5vUrOFn7WYdPtHCQVfnwbY4dpICh iJqssZaNNbFoR5Fx+1/ibgai/qtzymZl5qkg9jeSYRiOI/0d29Lb3hFwAgT9nwD5ea6T mAAOh513cKB4iiaebTY0CvBlZWguhRj/psDIV/GVWsFRZ2wL7SJi8nFCDLzCzLmIK5BA zwa9kz22c9WW7QzDyllwGNbrym2+biOt0alv/zZc6NBywrcgBb0OwvdDixnZnhZYLaI8 JemDl42HjAQDDCHs5T9+HKeikDgNvneef2YMLUHxYIiOAQ5z/HKqhd67SlDq1Ooqyum5 eI+g== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:mime-version :references:in-reply-to:message-id:date:subject:cc:to:from :dkim-signature; bh=PffYBtLGHbIcOZtzmyg9Rlu6xs5vVBU4yjNXSvTq6yI=; fh=lTKEK1Rt7LvnHRfa4w1cQ2RgMDufzBK6qxi+oKKQlPU=; b=MGxgxGEoG4jIT7ZPufTbQTSooz1yGat2iU4uXWZ3i+8LprJ9TsQOiUL0bH79RQ3ouU K3W2YiSyTU5msCKTAEE7pmEKQVTcMG45RgzjgOgQMz2whfEoxVtSv2imTuTNyXzUBpqe bc4Q3QVJfMqizv/wg1uNDD5S8epA2SCNk7NidULQXB9vojMdbgnuvpbKarHx4uRT5zna /JeH7Rczft1d9ujCuI9tTYKo1SSHDrxf6Cuji5xgb7SzvvXQfGIj1GoNsC36E1XCD7oM XAg5K3b7TA+odl5NIAAJqgKMrYQjRtTxwV1CwxyM1uesZWt0UCU6/JupytaWvcL0GrOU PO/g== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@kernel.org header.s=k20201202 header.b=heTtGtSe; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.31 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: from morse.vger.email (morse.vger.email. [23.128.96.31]) by mx.google.com with ESMTPS id fi1-20020a056a00398100b0068fa8499af1si17503207pfb.11.2023.10.13.05.00.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 13 Oct 2023 05:00:39 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.31 as permitted sender) client-ip=23.128.96.31; Authentication-Results: mx.google.com; dkim=pass header.i=@kernel.org header.s=k20201202 header.b=heTtGtSe; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.31 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: from out1.vger.email (depot.vger.email [IPv6:2620:137:e000::3:0]) by morse.vger.email (Postfix) with ESMTP id 94D2082E2962; Fri, 13 Oct 2023 05:00:36 -0700 (PDT) X-Virus-Status: Clean X-Virus-Scanned: clamav-milter 0.103.10 at morse.vger.email Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231755AbjJMMA2 (ORCPT + 19 others); Fri, 13 Oct 2023 08:00:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52148 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231734AbjJMMAA (ORCPT ); Fri, 13 Oct 2023 08:00:00 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1E459128; Fri, 13 Oct 2023 04:59:46 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 25A8EC433CA; Fri, 13 Oct 2023 11:59:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1697198386; bh=FQagvd3jim1vzLZluSHTIHqE/ZMRbbrLCQrXxKWYGq0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=heTtGtSecdsKYa7W/R1Z1z0SeOVDjYpQoDiPFINWnTuMzEiwro6TdB2AJ2E1nasyv /rUdpOgREj3kz73+hwtOZVonmWj1tgEz9Ox0diafReZahnnCNQh0ioxskwXb/j96/z qsM027GELQ42gdQvvLelfGRfuw9gn4Ydk/SkRj0RisnoS6Ih8rpGZXn3TNNAk83jB5 fiaudv4Ny0QD0cyGyUTYXLI9fqJYdfjkdlyYz9RMVKf9shSq+okffjMrLgQ2WCRYKR 023ipCxZezIXwWDvAB5G06Uifv5yUR7QMxPGDy5y5B54gR1EoVwA0nJb94m9hdK18i Wlg9YIpDberpw== From: Frederic Weisbecker To: LKML Cc: Frederic Weisbecker , Boqun Feng , Joel Fernandes , Josh Triplett , Mathieu Desnoyers , Neeraj Upadhyay , "Paul E . McKenney" , Steven Rostedt , Uladzislau Rezki , rcu Subject: [PATCH 13/18] rcu: Assume rcu_report_dead() is always called locally Date: Fri, 13 Oct 2023 13:58:57 +0200 Message-Id: <20231013115902.1059735-14-frederic@kernel.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20231013115902.1059735-1-frederic@kernel.org> References: <20231013115902.1059735-1-frederic@kernel.org> MIME-Version: 1.0 X-Spam-Status: No, score=-1.2 required=5.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on morse.vger.email Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-Greylist: Sender passed SPF test, not delayed by milter-greylist-4.6.4 (morse.vger.email [0.0.0.0]); Fri, 13 Oct 2023 05:00:36 -0700 (PDT) X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1779641550328760462 X-GMAIL-MSGID: 1779641550328760462 rcu_report_dead() has to be called locally by the CPU that is going to exit the RCU state machine. Passing a cpu argument here is error-prone and leaves the possibility for a racy remote call. Use local access instead. Reviewed-by: Paul E. McKenney Signed-off-by: Frederic Weisbecker --- arch/arm64/kernel/smp.c | 2 +- include/linux/rcupdate.h | 2 +- kernel/cpu.c | 2 +- kernel/rcu/tree.c | 4 ++-- 4 files changed, 5 insertions(+), 5 deletions(-) diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c index 960b98b43506..8fa646c90c67 100644 --- a/arch/arm64/kernel/smp.c +++ b/arch/arm64/kernel/smp.c @@ -401,7 +401,7 @@ void __noreturn cpu_die_early(void) /* Mark this CPU absent */ set_cpu_present(cpu, 0); - rcu_report_dead(cpu); + rcu_report_dead(); if (IS_ENABLED(CONFIG_HOTPLUG_CPU)) { update_cpu_boot_status(CPU_KILL_ME); diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index 5e5f920ade90..aa351ddcbe8d 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -122,7 +122,7 @@ static inline void call_rcu_hurry(struct rcu_head *head, rcu_callback_t func) void rcu_init(void); extern int rcu_scheduler_active; void rcu_sched_clock_irq(int user); -void rcu_report_dead(unsigned int cpu); +void rcu_report_dead(void); void rcutree_migrate_callbacks(int cpu); #ifdef CONFIG_TASKS_RCU_GENERIC diff --git a/kernel/cpu.c b/kernel/cpu.c index 6de7c6bb74ee..076e75fed8bb 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -1388,7 +1388,7 @@ void cpuhp_report_idle_dead(void) struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); BUG_ON(st->state != CPUHP_AP_OFFLINE); - rcu_report_dead(smp_processor_id()); + rcu_report_dead(); st->state = CPUHP_AP_IDLE_DEAD; /* * We cannot call complete after rcu_report_dead() so we delegate it diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 8c2954502e55..2e1e7eadf2cc 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -4560,11 +4560,11 @@ void rcu_cpu_starting(unsigned int cpu) * from the outgoing CPU rather than from the cpuhp_step mechanism. * This is because this function must be invoked at a precise location. */ -void rcu_report_dead(unsigned int cpu) +void rcu_report_dead(void) { unsigned long flags; unsigned long mask; - struct rcu_data *rdp = per_cpu_ptr(&rcu_data, cpu); + struct rcu_data *rdp = this_cpu_ptr(&rcu_data); struct rcu_node *rnp = rdp->mynode; /* Outgoing CPU's rdp & rnp. */ /*