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=-5.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS 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 0EE2CC2BA83 for ; Fri, 14 Feb 2020 17:58:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CEBCB22314 for ; Fri, 14 Feb 2020 17:58:13 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="CMxdoQEr" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388863AbgBNR6M (ORCPT ); Fri, 14 Feb 2020 12:58:12 -0500 Received: from us-smtp-1.mimecast.com ([207.211.31.81]:32537 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S2388546AbgBNR6J (ORCPT ); Fri, 14 Feb 2020 12:58:09 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1581703087; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=UACjdQjNAv3xbfQac1fzgBHkjusv+pnqBnjrSiF1gFM=; b=CMxdoQErykWNlqOZJzzkMS0oLPkkjdDUy8Al+Ju0pDXmaBh53OxzFi5TK7opxG8NfoEqlP O+TgPiH/3b3lVdnRVOLPolQHceTlC48tEp2Gg8E3aJ43PHQkInWBAwrFo9kzJwHCrtslof KRcfehrecSa2Z9AmkepMoImtkHtQ5TM= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-201-xzsdBgemOAGsM2iDbVFUUg-1; Fri, 14 Feb 2020 12:58:03 -0500 X-MC-Unique: xzsdBgemOAGsM2iDbVFUUg-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 4488D800D53; Fri, 14 Feb 2020 17:58:01 +0000 (UTC) Received: from treble (ovpn-121-12.rdu2.redhat.com [10.10.121.12]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 315429050E; Fri, 14 Feb 2020 17:58:00 +0000 (UTC) Date: Fri, 14 Feb 2020 11:57:58 -0600 From: Josh Poimboeuf To: Thomas Gleixner Cc: tip-bot2 for Josh Poimboeuf , linux-tip-commits@vger.kernel.org, Borislav Petkov , Julien Thierry , x86 , LKML , Nick Desaulniers Subject: Re: [tip: core/objtool] objtool: Fail the kernel build on fatal errors Message-ID: <20200214175758.s34rdwmwgiq6qwq7@treble> References: <158142525822.411.5401976987070210798.tip-bot2@tip-bot2> <20200213221100.odwg5gan3dwcpk6g@treble> <87sgjeghal.fsf@nanos.tec.linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <87sgjeghal.fsf@nanos.tec.linutronix.de> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Feb 14, 2020 at 01:10:26AM +0100, Thomas Gleixner wrote: > Josh Poimboeuf writes: > > On Tue, Feb 11, 2020 at 12:47:38PM -0000, tip-bot2 for Josh Poimboeuf wrote: > >> The following commit has been merged into the core/objtool branch of tip: > >> > >> Commit-ID: 644592d328370af4b3e027b7b1ae9f81613782d8 > >> Gitweb: https://git.kernel.org/tip/644592d328370af4b3e027b7b1ae9f81613782d8 > >> Author: Josh Poimboeuf > >> AuthorDate: Mon, 10 Feb 2020 12:32:38 -06:00 > >> Committer: Borislav Petkov > >> CommitterDate: Tue, 11 Feb 2020 13:27:03 +01:00 > >> > >> objtool: Fail the kernel build on fatal errors > >> > >> When objtool encounters a fatal error, it usually means the binary is > >> corrupt or otherwise broken in some way. Up until now, such errors were > >> just treated as warnings which didn't fail the kernel build. > >> > >> However, objtool is now stable enough that if a fatal error is > >> discovered, it most likely means something is seriously wrong and it > >> should fail the kernel build. > >> > >> Note that this doesn't apply to "normal" objtool warnings; only fatal > >> ones. > > > > Clang still has some toolchain issues which need to be sorted out, so > > upgrading the fatal errors is causing their CI to fail. > > Good. Last time we made it fail they just fixed their stuff. > > > So I think we need to drop this one for now. > > Why? It's our decision to define which level of toolchain brokeness is > tolerable. > > > Boris, are you able to just drop it or should I send a revert? > > I really want to see a revert which has a proper justification why the > issues of clang are tolerable along with a clear statement when this > fatal error will come back. And 'when' means a date, not 'when clang is > fixed'. Fair enough. The root cause was actually a bug in binutils which gets triggered by a new clang feature. So instead of reverting the above patch, I think I've figured out a way to work around the binutils bug, while also improving objtool at the same time (win-win). The binutils bug will be fixed in binutils 2.35. BTW, to be fair, this was less "Clang has issues" and more "Josh is lazy". I didn't test the patch with Clang -- I tend to rely on 0-day bot reports because I don't have the bandwidth to test the kernel/config/toolchain combinations. Nick tells me Clang will soon be integrated with the 0-day bot, which should help prevent this type of thing in the future. -- Josh