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=-1.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_PASS,T_DKIMWL_WL_HIGH,URIBL_BLOCKED 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 C203FC433F5 for ; Sat, 1 Sep 2018 09:50:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6036020843 for ; Sat, 1 Sep 2018 09:50:22 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="XaZX18Rn" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6036020843 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727247AbeIAOBq (ORCPT ); Sat, 1 Sep 2018 10:01:46 -0400 Received: from mail.kernel.org ([198.145.29.99]:58112 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725973AbeIAOBq (ORCPT ); Sat, 1 Sep 2018 10:01:46 -0400 Received: from devbox (NE2965lan1.rev.em-net.ne.jp [210.141.244.193]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id F26DF2083C; Sat, 1 Sep 2018 09:50:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1535795419; bh=f4vy5kd4FJ2ufc8eO90qGSTy27Q9Jtxw1pvhXhP0cWs=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=XaZX18RnDsnaH+CKwtIJVxzlGgoICpvOjLTYbl4JZzIiI3w9vWtn2G8OA+5kzU5Ah oob2DBkZiyAkSwW5U4HqZfwKQP6vlkvAAYWvy6DanRteZGfHZE5jBzvfMTtTJL7nBq ljZdobbY2hvSQN0A50qfNMOW8yXIJ+poQF6NlFEg= Date: Sat, 1 Sep 2018 18:50:17 +0900 From: Masami Hiramatsu To: Arnd Bergmann Cc: Stephen Rothwell , Steven Rostedt , Linux-Next Mailing List , Linux Kernel Mailing List Subject: Re: linux-next: build warnings from the build of Linus' tree Message-Id: <20180901185017.0a81bc3e61f5d021664f13f3@kernel.org> In-Reply-To: References: <20180824133206.4218c2e5@canb.auug.org.au> <20180824172053.20fa197294f51496dcec5605@kernel.org> <20180826035323.254463c8b183e6912c5b9a13@kernel.org> X-Mailer: Sylpheed 3.5.1 (GTK+ 2.24.31; x86_64-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Arnd, On Sat, 25 Aug 2018 21:53:17 +0200 Arnd Bergmann wrote: > On Sat, Aug 25, 2018 at 8:53 PM Masami Hiramatsu wrote: > > On Fri, 24 Aug 2018 14:46:16 +0200 > > Arnd Bergmann wrote: > > > On Fri, Aug 24, 2018 at 10:23 AM Masami Hiramatsu wrote: > > > > > > > > On Fri, 24 Aug 2018 13:32:06 +1000 > > > > Stephen Rothwell wrote: > > > > > > > > > Hi all, > > > > > > > > > > After merging the origin tree, today's linux-next build (powerpc > > > > > allyesconfig) produced these warnings: > > > > > > > > > > Maybe introduced by commit > > > > > > > > > > 6b7dca401cb1 ("tracing: Allow gcov profiling on only ftrace subsystem") > > > > > > > > > > I am guessing, but that is the only new thing that affects all of > > > > > kernel/trace ... > > > > > > > > Yes, I agree. But I just followed Documentation/dev-tools/gcov.rst > > > > to enable profiling in kernel/trace. Hmm, doesn't ppc64 support > > > > GCOV_PROFILE? (But as far as I can see, ARCH_HAS_GCOV_PROFILE_ALL > > > > is enabled in arch/powerpc/Kconfig) > > > > > > > > Anyway, I'll try to reproduce it. > > > > > > Thje same commit causes a link failure on ARM with a randconfig > > > kernel (see https://pastebin.com/KspjpyKG for the .config): > > > > OK, I confirmed that this happened with both gcc-7.3.0 and gcc-8.1.0 > > with your config. > > I also confirmed that CONFIG_GCOV_PROFILE_ALL causes same issue. > > (Note that CONFIG_GCOV_PROFILE_ALL depends on !CONFIG_COMPILE_TEST, > > so allyesconfig disables it always) > > > > Hmm, now gcov kernel itself might have a problem on arm and > > powerpc(on gcc-8)? > > Yes, that is very possible. I always force CONFIG_COMPILE_TEST=y > in my randconfig tests, so I miss that kind of problem. Finally, I've found that this issue (on arm) can be reproduced with a combination of config options. When CONFIG_BUG=n and CONFIG_GCOV_PROFILE_ALL|FTRACE=y on arm, this happened. If I set CONFIG_BUG=y, I could build the kernel without these errors. I also built on x86-64 with CONFIG_BUG=n & CONFIG_GCOV_PROFILE_FTRACE=y, but it succeeded. I guess arm kernel need to embed a counter near the code section. So if it is in .text.exit, it caused the error. On arch/arm/kernel/vmlinux.lds.h: #if (defined(CONFIG_SMP_ON_UP) && !defined(CONFIG_DEBUG_SPINLOCK)) || \ defined(CONFIG_GENERIC_BUG) || defined(CONFIG_JUMP_LABEL) #define ARM_EXIT_KEEP(x) x #define ARM_EXIT_DISCARD(x) #else #define ARM_EXIT_KEEP(x) #define ARM_EXIT_DISCARD(x) x #endif So I think we have to add CONFIG_GCOV_KERNEL to there. Thank you, -- Masami Hiramatsu