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=-1.0 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,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 C38FAC43387 for ; Tue, 18 Dec 2018 04:57:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8CF5F2133F for ; Tue, 18 Dec 2018 04:57:52 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=nifty.com header.i=@nifty.com header.b="F3JgDHTS" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726656AbeLRE5v (ORCPT ); Mon, 17 Dec 2018 23:57:51 -0500 Received: from conssluserg-03.nifty.com ([210.131.2.82]:23485 "EHLO conssluserg-03.nifty.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726316AbeLRE5u (ORCPT ); Mon, 17 Dec 2018 23:57:50 -0500 Received: from mail-vs1-f46.google.com (mail-vs1-f46.google.com [209.85.217.46]) (authenticated) by conssluserg-03.nifty.com with ESMTP id wBI4vXVU019335; Tue, 18 Dec 2018 13:57:33 +0900 DKIM-Filter: OpenDKIM Filter v2.10.3 conssluserg-03.nifty.com wBI4vXVU019335 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nifty.com; s=dec2015msa; t=1545109054; bh=mrACadVJh0wczd0rC2PscMxP+TZbM654Wxl8mmC2z0Q=; h=References:In-Reply-To:From:Date:Subject:To:Cc:From; b=F3JgDHTS2d2Rhv25RoTPEoLUJMnL1vTKzoHF1thVIadGiPstA95JKl6nYuf2+R7yo PrvUP14j1ottL1mWNXfghkogfqUYhzXNabWejz8ror/vtznzjW5oOWDgeGpLnNHzls Su+SeqGbbcSxfnscBXHbQ8o/sVMbd6r21R/msQceDFxFpZUCMf29YOej+gVW/OpMjE bzgLrYIDKdCplOkgeRsFW/kOSNUaWb8VTBjmmryPvViibpBslA/cFZR7MvpNRtb/VM Kyxu3cjtTOD8ykB4ljKPuOdIso3ZkHEkb9e4KBOf3a3GVkdDBHXyRubi1y+IxLu2tu UDzEO+1aClcUg== X-Nifty-SrcIP: [209.85.217.46] Received: by mail-vs1-f46.google.com with SMTP id p74so9237171vsc.0; Mon, 17 Dec 2018 20:57:33 -0800 (PST) X-Gm-Message-State: AA+aEWZJIAJt8HYR+5Kh8rWiGG4np7fGxLVGsS9K9YG4TfJW89vl6LSE 5Fp8Jket+rW5Wqf7PoTvLypR0KBXnlvNLZHp6iM= X-Google-Smtp-Source: AFSGD/XrMMW80X0/egSJ8zTZVC+n9dJz8ZepM2y0y+sJR8ZhiFMSGwE7Mdt5ONcE0w679QVotaCdtOztrmVxSP+mBx8= X-Received: by 2002:a67:a858:: with SMTP id r85mr7407662vse.215.1545109052681; Mon, 17 Dec 2018 20:57:32 -0800 (PST) MIME-Version: 1.0 References: <20171226043003.GB10431@windriver.com> <20171229021323.GF10431@windriver.com> <20171229164739.rgcqmam6wtno6hge@treble> <20171229181830.GH10431@windriver.com> <20181216214202.GQ11670@windriver.com> In-Reply-To: <20181216214202.GQ11670@windriver.com> From: Masahiro Yamada Date: Tue, 18 Dec 2018 13:56:56 +0900 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [Regression 4.15] Can't kill CONFIG_UNWINDER_ORC with fire or plague. To: Paul Gortmaker Cc: Josh Poimboeuf , Randy Dunlap , Ingo Molnar , Michal Marek , Linux Kbuild mailing list , Linux Kernel Mailing List Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Dec 17, 2018 at 6:45 AM Paul Gortmaker wrote: > > [Re: [Regression 4.15] Can't kill CONFIG_UNWINDER_ORC with fire or plague.] On 29/12/2017 (Fri 13:18) Paul Gortmaker wrote: > > > [Re: [Regression 4.15] Can't kill CONFIG_UNWINDER_ORC with fire or plague.] On 29/12/2017 (Fri 10:47) Josh Poimboeuf wrote: > > > > > This seems to be related to a kconfig quirk where only silentoldconfig > > > updates the include/config/auto.conf file. The other config targets > > > (oldconfig, defconfig, etc) don't touch it. It seems intentional, but I > > > have no idea why. > > > > > > That causes the Makefile to get stale data for 'CONFIG_*' variables when > > > it includes auto.conf. So I don't think this is specific to the ORC > > > check. It seems like it could also cause bugs elsewhere. > > > > OK, good - you agree with my initial diagnosis of stale auto.conf then. > > Not sure what Randy was testing when he said he couldn't reproduce it. > > > > > The below (ugly) patch fixes it, though I'm not sure this is the best > > > way to do it. We probably need Masahiro or Michal to chime in here. > > > > Yep, that is why I intentionally put the kbuild folks on the To/Cc of > > the original report (and ran away screaming at the prospect of debugging > > Makefiles on xmas day). But with holidays and all, it might not be > > until early January before they have a chance to reply. > > It is nearly a year later and we still have this false positive. > > paul@sm:~/git/linux-head$ make -j12 > /dev/null > Makefile:966: *** "Cannot generate ORC metadata for CONFIG_UNWINDER_ORC=y, > please install libelf-dev, libelf-devel or elfutils-libelf-devel". Stop. > paul@sm:~/git/linux-head$ grep UNWINDER_ORC .config > # CONFIG_UNWINDER_ORC is not set > > We do know a bit more now -- the auto.conf issue has been independently > confirmed and "fixed" for other subsystems/issues since, like RETPOLINE: > > --------------------- > commit 25896d073d8a0403b07e6dec56f58e6c33678207 > Author: Masahiro Yamada > Date: Wed Dec 5 15:27:19 2018 +0900 > > x86/build: Fix compiler support check for CONFIG_RETPOLINE > > It is troublesome to add a diagnostic like this to the Makefile > parse stage because the top-level Makefile could be parsed with > a stale include/config/auto.conf. > > Once you are hit by the error about non-retpoline compiler, the > compilation still breaks even after disabling CONFIG_RETPOLINE. > --------------------- > > I'm not sure if we want to treat this on a per config option each time > again and again, or undertake a more global kbuild approach, but it does > warrant a mention and a re-examination before we "solve" this again. I did not notice this thread (perhaps, it fell into my crack during the holidays) but I actually tried to fix this twice in a sophisticated way in the past. The first attempt (https://patchwork.kernel.org/patch/10516049/) was rejected by Josh Poimboeuf. The second one (https://patchwork.kernel.org/patch/10643245/) turned out not working as expected. Now, I am preparing for the third attempt, but it will take time for review. What I can do now is the similar fix-up as commit 25896d073d8. I will post a cheesy fix-up patch. -- Best Regards Masahiro Yamada