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=-8.3 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 EA529C3F2D2 for ; Fri, 28 Feb 2020 14:21:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BFB80246A0 for ; Fri, 28 Feb 2020 14:21:26 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=joelfernandes.org header.i=@joelfernandes.org header.b="dZgxgB/W" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726945AbgB1OVZ (ORCPT ); Fri, 28 Feb 2020 09:21:25 -0500 Received: from mail-qk1-f194.google.com ([209.85.222.194]:42966 "EHLO mail-qk1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725796AbgB1OVZ (ORCPT ); Fri, 28 Feb 2020 09:21:25 -0500 Received: by mail-qk1-f194.google.com with SMTP id o28so3041478qkj.9 for ; Fri, 28 Feb 2020 06:21:24 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=joelfernandes.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=zxTduCTfg/OrDpDovq9JnjmfGeVXyQFoQrsMpBvo3Ow=; b=dZgxgB/WmmtkL+gC2oCvv/1E5BKlgyBEvLQ2xCrhz6LQblwAVBlJxjky+Hz839DWks krQIYMWtkIgy7zmqyVkCkt43zuHpLcwXk2tF0PVXv895pVpU/SkY/FvJ0pAl34p6zn5K QGfDB8V9Ld3YPrttag7OxG/0HoI/XJtPV0tI4= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=zxTduCTfg/OrDpDovq9JnjmfGeVXyQFoQrsMpBvo3Ow=; b=q1z2xlOB6Dt/juxP/VnAILCylD5xvl543YMQuAYTyJo2hrgsWt1R3qTr2InjsS2ehG elrz4yGVS+DS3t2Zv5S85vGKg3YPuQuBpolyc8kQ5LtG4+P+hDw8HSmRXnQPqovDvlQ3 qmeGqIXOge0DOLYRL+ndYlI4qggOGE7I8XLJlmD4tQelOfh5tpnOoItc9rsLs1kDpYvE eJhNI/thacoRVAVWPb6r74LRoWVqZ794mtW+lt0bzpaNn9wzJ8gpvjyoJtmq5ZH3fXXQ Jjh5syCh7d4fWgoVPZv7/nMQmiGvxVB1D1OzEkt1YvURO38MDAvVDGcYoSqW3K7DLyYS muRw== X-Gm-Message-State: APjAAAWmQqTDEB6GdFX+CXQJCpesboZSEUl65aCQhVswFM2LoL9XInmh ONhSh7rn8vZh6ndksbUB+CRRiw== X-Google-Smtp-Source: APXvYqwsQWvWd/xsix8ctQluoCIEHDrjjsJMF1erCPPFZ/q4bQOKp13axSHWs6kQs2JP7QqCEdko1g== X-Received: by 2002:a37:b86:: with SMTP id 128mr4411810qkl.159.1582899684016; Fri, 28 Feb 2020 06:21:24 -0800 (PST) Received: from localhost ([2620:15c:6:12:9c46:e0da:efbf:69cc]) by smtp.gmail.com with ESMTPSA id b7sm5120708qtj.78.2020.02.28.06.21.23 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 28 Feb 2020 06:21:23 -0800 (PST) Date: Fri, 28 Feb 2020 09:21:22 -0500 From: Joel Fernandes To: madhuparnabhowmik10@gmail.com Cc: paulmck@kernel.org, josh@joshtriplett.org, rostedt@goodmis.org, mathieu.desnoyers@efficios.com, jiangshanlai@gmail.com, linux-kernel@vger.kernel.org, Amol Grover Subject: Re: [PATCH] Default enable RCU list lockdep debugging with PROVE_RCU Message-ID: <20200228142122.GA97131@google.com> References: <20200228092451.10455-1-madhuparnabhowmik10@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200228092451.10455-1-madhuparnabhowmik10@gmail.com> User-Agent: Mutt/1.12.2 (2019-09-21) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Feb 28, 2020 at 02:54:51PM +0530, madhuparnabhowmik10@gmail.com wrote: > From: Madhuparna Bhowmik > > This patch default enables CONFIG_PROVE_RCU_LIST option with > CONFIG_PROVE_RCU for RCU list lockdep debugging. > > With this change, RCU list lockdep debugging will be default > enabled in CONFIG_PROVE_RCU=y kernels. > > Most of the RCU users (in core kernel/, drivers/, and net/ > subsystem) have already been modified to include lockdep > expressions hence RCU list debugging can be enabled by > default. > > However, there are still chances of enountering > false-positive lockdep splats because not everything is converted, > in case RCU list primitives are used in non-RCU read-side critical > section but under the protection of a lock. It would be okay to > have a few false-positives, as long as bugs are identified, since this > patch only affects debugging kernels. > > Co-developed-by: Amol Grover > Signed-off-by: Amol Grover > Signed-off-by: Madhuparna Bhowmik Acked-by: Joel Fernandes (Google) thanks, - Joel > --- > kernel/rcu/Kconfig.debug | 11 +++-------- > 1 file changed, 3 insertions(+), 8 deletions(-) > > diff --git a/kernel/rcu/Kconfig.debug b/kernel/rcu/Kconfig.debug > index 4aa02eee8f6c..ec4bb6c09048 100644 > --- a/kernel/rcu/Kconfig.debug > +++ b/kernel/rcu/Kconfig.debug > @@ -9,15 +9,10 @@ config PROVE_RCU > def_bool PROVE_LOCKING > > config PROVE_RCU_LIST > - bool "RCU list lockdep debugging" > - depends on PROVE_RCU && RCU_EXPERT > - default n > + def_bool PROVE_RCU > help > - Enable RCU lockdep checking for list usages. By default it is > - turned off since there are several list RCU users that still > - need to be converted to pass a lockdep expression. To prevent > - false-positive splats, we keep it default disabled but once all > - users are converted, we can remove this config option. > + Enable RCU lockdep checking for list usages. It is default > + enabled with CONFIG_PROVE_RCU. > > config TORTURE_TEST > tristate > -- > 2.17.1 >