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=-12.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 8400BC07E96 for ; Tue, 13 Jul 2021 06:16:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6BD96611AB for ; Tue, 13 Jul 2021 06:16:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234138AbhGMGTU (ORCPT ); Tue, 13 Jul 2021 02:19:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44224 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233527AbhGMGTS (ORCPT ); Tue, 13 Jul 2021 02:19:18 -0400 Received: from mail-ed1-x536.google.com (mail-ed1-x536.google.com [IPv6:2a00:1450:4864:20::536]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1591EC0613DD; Mon, 12 Jul 2021 23:16:29 -0700 (PDT) Received: by mail-ed1-x536.google.com with SMTP id dj21so11738307edb.0; Mon, 12 Jul 2021 23:16:28 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=N755/myeCrFum8G4UCZxfG01d/TQE+qL8ItRnH1D5gI=; b=pXz+WHI4SxVPWbrRwY10B1qhwgIE/zrSu4mRkL0qK8d4r9paEjbkjQfkFpaZtqmVMK F40mIful9n8Hvv3rIK9o1hkcQOCUVWD6H+SyCWGrAkbdmR4p93+TDVpE7KJFN92zkG/E FyCnO2J7m+vTrYVfmo6m+ClTgGhQJm2Aatailw7a+mDrmUIFi58cjWNQQ1/pQCClfBeA oTyeVEoMn29b7ft9tqSRx8MT005DtAWbzCRNcj0v8GvRJOTh5TAX4QafCZLNjmZzDOG6 OQZCr0gvK3XXzaXpVR43xFkRAZrpiCP1uaM7fposNnFK+CMVlpJQrX+LizSEqy3JqYVm l8Xw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=N755/myeCrFum8G4UCZxfG01d/TQE+qL8ItRnH1D5gI=; b=oyw8BUMnHGMtL+DjEjiuwEWfNhj9bOGsBVivudn+I7sPactiUmbVuspKXEn/di4Hbs a/KbBiL1G3HjNNvVr0+RjDFjIyeDU1FZuQVe0WTObPHTnMBxzPudPo9qnVD8eZUoDZft Jf0m2scUjDh/td1mBHDlUgHCWvJ9epyUsNk1A+Bmfygb98BhvnXEHV2+4EoidJmQYs7f 0GzJigY7FQCp+ZaxuXlO/QaThlv51XO3aBnO2CQEzLP9Hr4jeerihWh74gcW+5rWgcV1 p4tBHcmNBSqau7jm6uyis48yaejh1sWLUibLUGG/1YXs5hw/3JhJWwLYl1GG5jweITIb f7uQ== X-Gm-Message-State: AOAM533ofEHrhVhuFQe8ndcSwuSfN2dZS1g0rtiHu0jvv+Kv4Ls1dkVq G8oWxspH98lg+NUrO4qyqn82Qq45S6rUspBwzCI= X-Google-Smtp-Source: ABdhPJxb0+N6WRj/GhOgT8oAWNKUlDO67rCxa3DafGwy9Sn1/gVH+bGkHx6Xzi1nAdNDJzbcMFXTnCOalpKU40BOBb4= X-Received: by 2002:a05:6402:3192:: with SMTP id di18mr3538469edb.186.1626156987630; Mon, 12 Jul 2021 23:16:27 -0700 (PDT) MIME-Version: 1.0 References: <20210713005645.8565-1-zhouzhouyi@gmail.com> <20210713041607.GU4397@paulmck-ThinkPad-P17-Gen-1> In-Reply-To: <20210713041607.GU4397@paulmck-ThinkPad-P17-Gen-1> From: Zhouyi Zhou Date: Tue, 13 Jul 2021 14:16:15 +0800 Message-ID: Subject: Re: [PATCH] RCU: Fix macro name CONFIG_TASKS_RCU_TRACE To: paulmck@kernel.org Cc: josh@joshtriplett.org, rostedt@goodmis.org, mathieu.desnoyers@efficios.com, jiangshanlai@gmail.com, joel@joelfernandes.org, rcu@vger.kernel.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Thank you very much, I went through the wordsmithed version, it looks exquisite! Thank you for your encouragement. Cheers Zhouyi On Tue, Jul 13, 2021 at 12:16 PM Paul E. McKenney wrote: > > On Tue, Jul 13, 2021 at 08:56:45AM +0800, zhouzhouyi@gmail.com wrote: > > From: Zhouyi Zhou > > > > Hi Paul, > > > > During my studying of RCU, I did a grep in the kernel source tree. > > I found there are 3 places where the macro name CONFIG_TASKS_RCU_TRACE > > should be CONFIG_TASKS_TRACE_RCU instead. > > > > Without memory fencing, the idle/userspace task inspection may not > > be so accurate. > > > > Thanks for your constant encouragement for my studying. > > > > Best Wishes > > Zhouyi > > > > Signed-off-by: Zhouyi Zhou > > Good eyes, and those could cause real bugs, so thank you! > > Could you please check the wordsmithed version below? > > Thanx, Paul > > ------------------------------------------------------------------------ > > commit fdcf5524b64f2cc8e6201447644079d9f8d4c821 > Author: Zhouyi Zhou > Date: Tue Jul 13 08:56:45 2021 +0800 > > RCU: Fix macro name CONFIG_TASKS_RCU_TRACE > > This commit fixes several typos where CONFIG_TASKS_RCU_TRACE should > instead be CONFIG_TASKS_TRACE_RCU. Among other things, these typos > could cause CONFIG_TASKS_TRACE_RCU_READ_MB=y kernels to suffer from > memory-ordering bugs that could result in false-positive quiescent > states and too-short grace periods. > > Signed-off-by: Zhouyi Zhou > Signed-off-by: Paul E. McKenney > > diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h > index cfeb43bfc719..434d12fe2d4f 100644 > --- a/include/linux/rcupdate.h > +++ b/include/linux/rcupdate.h > @@ -167,7 +167,7 @@ void synchronize_rcu_tasks(void); > # define synchronize_rcu_tasks synchronize_rcu > # endif > > -# ifdef CONFIG_TASKS_RCU_TRACE > +# ifdef CONFIG_TASKS_TRACE_RCU > # define rcu_tasks_trace_qs(t) \ > do { \ > if (!likely(READ_ONCE((t)->trc_reader_checked)) && \ > diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h > index 27b74352cccf..a8e3acead6f6 100644 > --- a/kernel/rcu/tree_plugin.h > +++ b/kernel/rcu/tree_plugin.h > @@ -1498,17 +1498,17 @@ static void noinstr rcu_dynticks_task_exit(void) > /* Turn on heavyweight RCU tasks trace readers on idle/user entry. */ > static void rcu_dynticks_task_trace_enter(void) > { > -#ifdef CONFIG_TASKS_RCU_TRACE > +#ifdef CONFIG_TASKS_TRACE_RCU > if (IS_ENABLED(CONFIG_TASKS_TRACE_RCU_READ_MB)) > current->trc_reader_special.b.need_mb = true; > -#endif /* #ifdef CONFIG_TASKS_RCU_TRACE */ > +#endif /* #ifdef CONFIG_TASKS_TRACE_RCU */ > } > > /* Turn off heavyweight RCU tasks trace readers on idle/user exit. */ > static void rcu_dynticks_task_trace_exit(void) > { > -#ifdef CONFIG_TASKS_RCU_TRACE > +#ifdef CONFIG_TASKS_TRACE_RCU > if (IS_ENABLED(CONFIG_TASKS_TRACE_RCU_READ_MB)) > current->trc_reader_special.b.need_mb = false; > -#endif /* #ifdef CONFIG_TASKS_RCU_TRACE */ > +#endif /* #ifdef CONFIG_TASKS_TRACE_RCU */ > }