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=-5.3 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,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 ABB44C3F2D2 for ; Thu, 5 Mar 2020 17:40:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7E8C620848 for ; Thu, 5 Mar 2020 17:40:05 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="qMqAXVvp" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726170AbgCERkE (ORCPT ); Thu, 5 Mar 2020 12:40:04 -0500 Received: from mail-pl1-f194.google.com ([209.85.214.194]:46762 "EHLO mail-pl1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725938AbgCERkE (ORCPT ); Thu, 5 Mar 2020 12:40:04 -0500 Received: by mail-pl1-f194.google.com with SMTP id w12so2769680pll.13 for ; Thu, 05 Mar 2020 09:40:02 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:date:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=Fwow6K7jsM635u4hX7uuA9k3vOkPSqTTypNUyW6/TUY=; b=qMqAXVvphxubq/lxkcZ85TqcPWB9iEOe7HMOwCW0BoGX157x/CVL9Bmy5s0JRX44j1 1BA2lRXB0a4OJqQo3McZFfbhbU63nhep8v9tfp8T7KMErGp/N6jZXZFHAHB9ojJzw3RL lYAQB6JT1FsqgJjQGkjZ3OY9Rczgbq94Oemnxkj9Yx+8/TR4jnoRycjJ3DCehlKgss9r KdYG7gw/vEe+hnsa7JGbkqgVgSBn5QG2fYyx37bJq8TqnDvTV0bIoTG8cdlL1iBbeqhg 8KDdIhmJryfaxjXNzebYoXuiCtohwx/D/yOQdIiZ0yF2k2SReOgY7jH3fN1+dQEEFiTJ rRog== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:date:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=Fwow6K7jsM635u4hX7uuA9k3vOkPSqTTypNUyW6/TUY=; b=sDELOVTdnmyc12jDNY+h1GiB1YDRJpl/H2xIDfm/1GooU97rTOMudxMyvfr+G0+acP cwwOe9L2p+Wo+iqLlO+XJE3iviOzOfMOjM+hDVrCcKCQDbQTPdm5E0O681x4Tkizr2MJ A7DlPggoGjT6tR/uB7+Aq2wytfOScnVNT64hNvGAyqiy98ZFAc6GlYInjwYjp9mnlzQK 1Xnix9JF2KcOYyquSdwGIcv9KS9Zl68agx4NKrACzQrQcDj8dVwji8tlzQh+nECySJZz tj/yXOfC77T7IQi8kGsd5g9mt8g1d886mQxNFSC0isLX439ai8YszgpoYUdsPGxgNYYK /nxw== X-Gm-Message-State: ANhLgQ0kvEN4Tq+9ebA25jgKOoUQZFyPUTeO4N26/nbU4xpQpN7QgruY 8aQy9WU9KsGIxoOLvY214m8sCCI= X-Google-Smtp-Source: ADFU+vsEiecdkVptIoIkzpBcZJEM2BircXIFYz4xLout7u/nfoCzPAi1DZqkZ2ny15wjU2cu5gcSOw== X-Received: by 2002:a17:902:8b8a:: with SMTP id ay10mr9372833plb.288.1583430001634; Thu, 05 Mar 2020 09:40:01 -0800 (PST) Received: from madhuparna-HP-Notebook ([2402:3a80:1ee0:fa4c:45f1:8421:bfd8:b0fb]) by smtp.gmail.com with ESMTPSA id y18sm31808475pfe.19.2020.03.05.09.39.57 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Thu, 05 Mar 2020 09:40:00 -0800 (PST) From: Madhuparna Bhowmik X-Google-Original-From: Madhuparna Bhowmik Date: Thu, 5 Mar 2020 23:09:54 +0530 To: Guenter Roeck Cc: madhuparnabhowmik10@gmail.com, paulmck@kernel.org, josh@joshtriplett.org, rostedt@goodmis.org, mathieu.desnoyers@efficios.com, jiangshanlai@gmail.com, joel@joelfernandes.org, linux-kernel@vger.kernel.org, Amol Grover Subject: Re: [PATCH] Default enable RCU list lockdep debugging with PROVE_RCU Message-ID: <20200305173953.GA10538@madhuparna-HP-Notebook> References: <20200228092451.10455-1-madhuparnabhowmik10@gmail.com> <20200305155238.GA8669@roeck-us.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200305155238.GA8669@roeck-us.net> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Mar 05, 2020 at 07:52:38AM -0800, Guenter Roeck wrote: > 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 > > Who is going to fix the fallout ? > > fs/btrfs/block-group.c:2011 RCU-list traversed in non-reader section!! > kernel/kprobes.c:329 RCU-list traversed in non-reader section!! > net/ipv4/ipmr.c:136 RCU-list traversed in non-reader section!! > Hi, There is already a patch for fixing the warnings in kernel/kprobes.c : https://lore.kernel.org/lkml/157905963533.2268.4672153983131918123.stgit@devnote2/ Same for net/ipv4/ipmr: https://lore.kernel.org/patchwork/patch/1198934/ Can you please send the warning with the stack backtrace and locks held for btrfs/block-group.c, I will work on it. Thank you, Madhuparna > This is just from my boot tests. I'll keep PROVE_RCU enabled for the > time being, but unless the noise is addressed I'll have to disable it > because otherwise the real problems disappear in the noise. > > Guenter