Received: by 2002:a25:ab43:0:0:0:0:0 with SMTP id u61csp7730112ybi; Thu, 6 Jun 2019 00:10:28 -0700 (PDT) X-Google-Smtp-Source: APXvYqxdpS1Fgf1zDbRY5AB695URSAeVxe6+Evvv9sfkBi1SfYkl1kPuW0k7GSl18hT+yGLTiiFD X-Received: by 2002:a17:902:b70b:: with SMTP id d11mr49793725pls.84.1559805028775; Thu, 06 Jun 2019 00:10:28 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1559805028; cv=none; d=google.com; s=arc-20160816; b=ZZn/vDlw8wTZdGFgveR75VJ91WNR15Jy3UPkNo75fIO7AP8KdnpnHjwJ83ky7zEN0V J094PLF7njXt6MIBT+SpIhFKl+FaaKP7WD3Pla6I0xRA2H9U93qi5iGKBzWpu4gAPhTv 2dzaCvj+iA+vRAHQ+bh3y/3dHmDFgE/RK7EzVSmouCPE3VC8Q2dPqfWVt60ep0xR0srf phSdk46Acn4KOptd9CD0vT6RiWSejDFG1PG/dPvFoqfgq85xrGyi+Km5xWkj/G4UDqhH jMAIp+KbtNl+DuLnWpki0wFP0v0leLLXOg94Cy3nmOKb9min86vUBt4uSS4jmLvIiLS3 3P+g== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:user-agent:in-reply-to :content-disposition:mime-version:references:message-id:subject:cc :to:from:date:dkim-signature; bh=lQzKSNyPtL6PVtmkpLeXCzwFS9EgwnNkThBhd0dii4Y=; b=q1U05cudFnHGt9GqlRm79OJ0j5q05z0ErwOI7tWxycvdlRApbDJ0as9Ssgyz22w9Mq XaiIU6rM4BUH35g+Orw1W2hJkSBbmHasXmihmdJH+bfG+niUdAro/F1PtSsfArrJMK4z hRAcMWx4gL0mmxY7BdsktfyIHryOHdggUQ5sskn6TAwIW0ZsbQfqYeUsvLk3KzXt3tWL HzhYkNbu0u33SyLG+7rHxDukcztGOgCbdglw307E5fgKQ5vBlqSXf0HQozff8yMAnzf7 or5sUKZl/Y2oP4KXQcqa0yzeD1eT/tzAoGbmF4bgLNu5fCppGJgzhXxpnBPszIpXASaX /oOg== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b=VmXsfdmV; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id 16si1147380pfu.100.2019.06.06.00.10.12; Thu, 06 Jun 2019 00:10:28 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b=VmXsfdmV; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726721AbfFFHIL (ORCPT + 99 others); Thu, 6 Jun 2019 03:08:11 -0400 Received: from mail.kernel.org ([198.145.29.99]:43036 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725782AbfFFHIK (ORCPT ); Thu, 6 Jun 2019 03:08:10 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (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 B3CDA2083D; Thu, 6 Jun 2019 07:08:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1559804889; bh=sOq1aIPwoGF1dlKwf8g6qXJnPdLXODwo9qjIaiPRjr4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=VmXsfdmVy+fYk40zwh0ypfxRSF+bHgzmqyKHAiM+pwFTnrkAYrmCy4z6OTf5t0zFp +i6i3PMpxynsI4LQIarHQz/erzaloaH+NgO6vu4I8GL0Ug4OinVxnYitknMlGd1KDv 5OIG5iFXvxUcXdZFqCU1PpD43K9Fp16HZ8wVeVgo= Date: Thu, 6 Jun 2019 09:08:07 +0200 From: Greg KH To: Ard Biesheuvel Cc: Nick Desaulniers , Rolf Eike Beer , Linus Torvalds , Matt Fleming , Peter Zijlstra , Thomas Gleixner , linux-efi , Linux Kernel Developers List , stable , clang-built-linux Subject: Re: Building arm64 EFI stub with -fpie breaks build of 4.9.x (undefined reference to `__efistub__GLOBAL_OFFSET_TABLE_') Message-ID: <20190606070807.GA17985@kroah.com> References: <779905244.a0lJJiZRjM@devpool35> <20190605162626.GA31164@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.12.0 (2019-05-25) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jun 06, 2019 at 08:55:29AM +0200, Ard Biesheuvel wrote: > On Wed, 5 Jun 2019 at 22:48, Nick Desaulniers wrote: > > > > On Wed, Jun 5, 2019 at 11:42 AM Ard Biesheuvel > > wrote: > > > For the record, this is an example of why I think backporting those > > > clang enablement patches is a bad idea. > > > > There's always a risk involved with backports of any kind; more CI > > coverage can help us mitigate some of these risks in an automated > > fashion before we get user reports like this. I meet with the > > KernelCI folks weekly, so I'll double check on the coverage of the > > stable tree's branches. The 0day folks are also very responsive and > > I've spoken with them a few times, so I'll try to get to the bottom of > > why this wasn't reported by either of those. > > > > Also, these patches help keep Android, CrOS, and Google internal > > production kernels closer to their upstream sources. > > > > > We can't actually build those > > > kernels with clang, can we? So what is the point? > > > > Here's last night's build: > > https://travis-ci.com/ClangBuiltLinux/continuous-integration/builds/114388434 > > > > If you are saying that plain upstream 4.9-stable defconfig can be > built with Clang, then I am pleasantly surprised. I know some specific configs can, there's no rule that I know of that 'defconfig' support is required. But then again, it might also work, try it and see :) > > Also, Android and CrOS have shipped X million devices w/ 4.9 kernels > > built with Clang. I think this number will grow at least one order of > > magnitude imminently. > > > > I know that (since you keep reminding me :-)), but obviously, Google > does not care about changes that regress GCC support. What are you talking about? Bugs happen all the time, what specifically did "Google" do to break gcc support? If you are referring to this patch, and it is a regression, of course I will revert it. But note that gcc and 4.9 works just fine for all of the other users right now, remember we do do a lot of testing of these releases. thanks, greg k-h