From nobody Fri Jan 2 01:35:06 2026 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 C5199CDB474 for ; Tue, 17 Oct 2023 08:51:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234673AbjJQIvF (ORCPT ); Tue, 17 Oct 2023 04:51:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37472 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234620AbjJQIvD (ORCPT ); Tue, 17 Oct 2023 04:51:03 -0400 Received: from out203-205-221-192.mail.qq.com (out203-205-221-192.mail.qq.com [203.205.221.192]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A8F50ED for ; Tue, 17 Oct 2023 01:51:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=foxmail.com; s=s201512; t=1697532658; bh=9uFm1swz/WuySLvKGXHbXWNCQTdIg19qp5EJ/O34ajM=; h=From:To:Subject:Date; b=BKRcoewoyh47KFeApgMNZ1G63acF/V+DNlaQ1/0h/GrGh2BprmZP3ySAX0eRrw9RR G/ZQNGAleU3e2LSg2llJx9JCSaIsDH8/W9n9xuvj2PRkz9xskTRSgWybxmc+iyogOg fosNjUDAnhV4jCxE/xdqQAf+OvEqBM6IRwT5Ku5I= Received: from RT-NUC.. ([39.156.73.12]) by newxmesmtplogicsvrszc5-0.qq.com (NewEsmtp) with SMTP id CB837072; Tue, 17 Oct 2023 16:50:56 +0800 X-QQ-mid: xmsmtpt1697532656ti2ncg7rd Message-ID: X-QQ-XMAILINFO: MyIXMys/8kCtt4y1uxNGwZpRB3usmzxHRUaiJ+PZ0Y6gfxbVLShGIS5D6Yyldu aWbS43+6OvJjA9YQ3nK4x8QBLmqvkx3a9iPvIBrXfO1WiQuzHq/WhTlqvLcIlk0pzk3o62bJ+3o9 wiXzBI0+i+L2t70AmnUW6C80wO6izz6Hwh6h0qscGqRJB5g7edjcE9h/7xJnlCOuBd5PWEv775jG Vq6eDiRRPZj81D63BiX5nEkF5dGUpNs6NYx0Cz86foBbQtHpk7aBCjXSF0h4lc8Oaw3byjJAi34y nNC+IpKFnVGFiKRFtGiDS3YdIq/0EktKed+lUfNcZ2mlJ3KtchAqnPDMFWOfDJ6XKRhmYQIDTqgc po5iHAawCC2DHvkquY+cj/swh2YNCVzC/DdvJIuRRDt7CPfFsFs5yNUS7D26CN6yO0NZ0eyiztqE 8ijyplOxawiTUgP6os1l+5Ry/zBsa+12D7r/AZFHaZJqoe/q9HEphNf8pOUQuLBxWKUKRaFoPIl9 Lyw/S94gFR9smyjBeVlAA6A44n0tBF/e0bzGqUBVTssmmL0CCzsTXryGMWFJAFTHFLz2prvoXIEI YUDnN/Q4iiIoDQSMkHHKi1f0pVUATWegwqF5LOn2WPrKHIb3mcMye5s31Fn1UCqsNevOLBarR492 oCa2t8i+B+NCLvIl2ZE2U4yiS8L6IJKIzIJTrA8rdVWrvd0xi1f0UgZF/DmrCjyecFxaaB18MPa4 4yg+x7jtDX2Fv6udOTcEHhkmo3nalpaE5xVJ6X9/GBL/7Y4l5cCpNCSL6yueGc0ji6InaMluL7jp sHOz1+5XzqY1qzlO2g9yljiQCbF1x+mz2j1ShTUu0BjoZXiuLYsY54satbG7AR+S2q8ADOOISM+I JW5PDwakYLPQO7HSScp3Jq4bEWjr948udXtSsoOioMuYcERKQduHreIoVY0DPWu/0TXhCR5n6LQq wyk9KRkNXlBq/W/oMu7Q== X-QQ-XMRINFO: MPJ6Tf5t3I/ycC2BItcBVIA= From: Rong Tao To: mark.rutland@arm.com, elver@google.com, tglx@linutronix.de, peterz@infradead.org, Rong Tao , linux-kernel@vger.kernel.org (open list) Subject: [PATCH] stop_machine: Avoid potential race behaviour of multi_stop_data::state Date: Tue, 17 Oct 2023 16:50:52 +0800 X-OQ-MSGID: <20231017085053.263070-1-rtoax@foxmail.com> X-Mailer: git-send-email 2.42.0 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Rong Tao In commit b1fc58333575 ("stop_machine: Avoid potential race behaviour") fix both multi_cpu_stop() and set_state() access multi_stop_data::state, We should ensure that multi_stop_data::state is accessed using the rwonce method. Signed-off-by: Rong Tao --- kernel/stop_machine.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/stop_machine.c b/kernel/stop_machine.c index cedb17ba158a..73de9ab77132 100644 --- a/kernel/stop_machine.c +++ b/kernel/stop_machine.c @@ -191,7 +191,7 @@ static void set_state(struct multi_stop_data *msdata, static void ack_state(struct multi_stop_data *msdata) { if (atomic_dec_and_test(&msdata->thread_ack)) - set_state(msdata, msdata->state + 1); + set_state(msdata, READ_ONCE(msdata->state) + 1); } =20 notrace void __weak stop_machine_yield(const struct cpumask *cpumask) --=20 2.42.0