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=-0.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no 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 9DD39C38A2A for ; Fri, 8 May 2020 16:20:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 71AD621473 for ; Fri, 8 May 2020 16:20:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="V6L8Y736" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727051AbgEHQUz (ORCPT ); Fri, 8 May 2020 12:20:55 -0400 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:53045 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726767AbgEHQUz (ORCPT ); Fri, 8 May 2020 12:20:55 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1588954853; 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=H62jLWxF6mJP38xdlMPJYxyincWvSwp41kLYheQf1ro=; b=V6L8Y736Rb7GMBelC2j6te2s2aGnRg5tKRZf2CcOoWFEJM1jrKZ0iwHhATM6QIhMPtE2UV 9qdzfMVKmcGvgxsGuV/jqfm8b4e/cy31hDoJzeoVj3SoYVhPaPFoQ7/Dui7arSYskCMeLY nC8UVJ3lLZMg/s4CsftlUmKLeR8no2E= 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-193-PGyXSKFTNyuckXST9GaQVA-1; Fri, 08 May 2020 12:20:52 -0400 X-MC-Unique: PGyXSKFTNyuckXST9GaQVA-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 263DF872FE2; Fri, 8 May 2020 16:20:51 +0000 (UTC) Received: from treble (ovpn-115-96.rdu2.redhat.com [10.10.115.96]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 18A0A341FC; Fri, 8 May 2020 16:20:49 +0000 (UTC) Date: Fri, 8 May 2020 11:20:47 -0500 From: Josh Poimboeuf To: Peter Zijlstra Cc: Arnd Bergmann , Linux Kernel Mailing List Subject: Re: objtool warning breaks build for fs/dlm/lock.o Message-ID: <20200508162047.cwdhuonz4jjnnsc5@treble> References: <20200507232941.jccuywl56bppxfyp@treble> <20200508094518.GW5298@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20200508094518.GW5298@hirez.programming.kicks-ass.net> X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, May 08, 2020 at 11:45:18AM +0200, Peter Zijlstra wrote: > On Thu, May 07, 2020 at 06:29:41PM -0500, Josh Poimboeuf wrote: > > On Wed, May 06, 2020 at 04:07:25PM +0200, Arnd Bergmann wrote: > > > Hi, > > > > > > During randconfig testing with clang-10 I came across a number > > > of additional objtool warnings, I'll send another mail about those > > > when I have collected more information and some object files. > > > > > > This one sticks out however, as objtool returns an error code that > > > stops the build: > > > > > fs/dlm/lock.o: warning: objtool: __receive_convert_reply()+0x1e5: can't find jump dest instruction at .text+0xcaa7 > > > > Thanks for sending the patch for this one. Objtool always gets confused > > by new compiler versions, I really think we need to revert > > > > 644592d32837 ("objtool: Fail the kernel build on fatal errors") > > > > because objtool is never going to be reliable enough such that we can be > > confident that failing the build is the right thing to do. > > So on the one hand I agree. We're forever playing catch up with the > compilers, and as I said earlier, objtool generating an error has the > very unfortunate effect of the actual .o file getting deleted by the > build system, which is all sorts of annoying when you then want to > figure out what objtool got upset about. > > So, yes, we probably should revert that. > > OTOH, if we don't break the build, people are going to continue to > ignore objtool warnings/errors when they writes new code. True, but they can already do that anyway since right now it only fails on fatal warnings. -- Josh