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=-12.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,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 3A55EC2B9F8 for ; Tue, 25 May 2021 04:18:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F2A5061157 for ; Tue, 25 May 2021 04:18:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230222AbhEYEUP (ORCPT ); Tue, 25 May 2021 00:20:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50066 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229446AbhEYEUO (ORCPT ); Tue, 25 May 2021 00:20:14 -0400 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:e::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id ACBB2C061574 for ; Mon, 24 May 2021 21:18:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=Content-Transfer-Encoding: Content-Type:In-Reply-To:MIME-Version:Date:Message-ID:From:References:Cc:To: Subject:Sender:Reply-To:Content-ID:Content-Description; bh=0EGd2U/04FlaESkoL8bnAvy5F/5fb4NYWjnc+HfDQxA=; b=kQPCx4iFbYAwd+aFzAg8p/Lh2y p9sHL81BwagkAQWru7RiUv6HB0aYvzfPn0sTB45xxuewNlqxPA5YJidUeZqpiWJAO8zKR+qh8NhiK Md3Qd5FU0YYAZSRGsBkhH80P8MWaL11j0aTXWY6Ct+VUGD+2FZOIotNVnqAeQK6WiPb3OXE532lG/ Jeq2nmds0gMWXMxi7UiFI2HnvUPP77Pzk77dfG8Y4jWpGj26ohx74IhQk70YmQtYXcFad5Fj37j9o vJR+055eCfaz6c+Ux3AFUThfZNk8nV9aiKlItB92EI0Oco9an2D9ZaGkKq04/KKcdSijrpWxwgBm6 gIbQqy5Q==; Received: from [2601:1c0:6280:3f0::7376] by bombadil.infradead.org with esmtpsa (Exim 4.94 #2 (Red Hat Linux)) id 1llOWT-003IKs-Qh; Tue, 25 May 2021 04:18:29 +0000 Subject: Re: [PATCH] LOCKDEP: use depends on LOCKDEP_SUPPORT instead of $ARCH list To: Waiman Long , Ingo Molnar Cc: linux-kernel@vger.kernel.org, Peter Zijlstra , Ingo Molnar , Will Deacon , Boqun Feng , Chris Zankel , Max Filippov , linux-xtensa@linux-xtensa.org, Johannes Berg , Jeff Dike , Richard Weinberger , Anton Ivanov , linux-um@lists.infradead.org References: <20210517034430.9569-1-rdunlap@infradead.org> <1284b997-b9da-769f-2d36-4d4232c7df88@redhat.com> <8a4ee5be-ad5c-ca06-dd1a-aa13ccc94906@redhat.com> <09243238-94ba-caca-441e-3fdac0154822@infradead.org> <3a0fb04c-c640-25db-7e7a-fbdd3b4defb5@redhat.com> From: Randy Dunlap Message-ID: <0213cd4e-e832-f768-106a-345e77ce2665@infradead.org> Date: Mon, 24 May 2021 21:18:26 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.10.0 MIME-Version: 1.0 In-Reply-To: <3a0fb04c-c640-25db-7e7a-fbdd3b4defb5@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 5/24/21 5:05 PM, Waiman Long wrote: > On 5/24/21 5:41 PM, Randy Dunlap wrote: >> On 5/24/21 2:31 PM, Randy Dunlap wrote: >>> On 5/24/21 2:04 PM, Waiman Long wrote: >>> >>>> Is it possible to just get rid of the 2nd depends-on statement? >>>> >>>> The 2nd depends-on line was introduced by commit 7d37cb2c912d ("lib: fix kconfig dependency on ARCH_WANT_FRAME_POINTER"): >>> and I should have looked at that history too. Thanks. >>> >>> Yes, I agree, we can just delete that line... >>> >>> I'll send a v2 and copy the author of commit 7d37cb2c912d as well. >> Hm, as I review that commit, I have to wonder if the previous 'select' >> was correct (if we disregard the Kconfig warning).  If so, then >> FRAME_POINTER is still wanted/needed for some arch-es. >> >> diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug >> index 2779c29d9981..417c3d3e521b 100644 >> --- a/lib/Kconfig.debug >> +++ b/lib/Kconfig.debug >> @@ -1363,7 +1363,7 @@ config LOCKDEP >>          bool >>          depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT >>          select STACKTRACE >> -       select FRAME_POINTER if !MIPS && !PPC && !ARM && !S390 && !MICROBLAZE && !ARC && !X86 <<<<<<<<<<< >> > AFAICS, enabling FRAME_POINTER is a debugging aid as it enable more precise stacktrace. However, not all archs want to enable FRAME_POINTER because of LOCKDEP. Now you are just letting users decide if they want FRAME_POINTER or not. Maybe you can modify the help text to mention that. LOCKDEP doesn't have any user help text. For FRAME_POINTER, when ARCH_WANT_FRAME_POINTERS + a few other conditions is met, it seems that the FRAME_POINTER help text is good enough IMO. help If you say Y here the resulting kernel image will be slightly larger and slower, but it gives very useful debugging information in case of kernel bugs. (precise oopses/stacktraces/warnings) -- ~Randy