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=-5.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 46C07C64E7A for ; Tue, 1 Dec 2020 08:20:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D86AA2087D for ; Tue, 1 Dec 2020 08:20:11 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="t902PH78" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728527AbgLAIT4 (ORCPT ); Tue, 1 Dec 2020 03:19:56 -0500 Received: from mail.kernel.org ([198.145.29.99]:47176 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728193AbgLAITz (ORCPT ); Tue, 1 Dec 2020 03:19:55 -0500 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (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 7FEFD2085B; Tue, 1 Dec 2020 08:19:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1606810755; bh=0/yOIYQ98fm3d3u1FxrZ+6Y5Jj/gTetcUK3rSD1zAa4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=t902PH78vejIKt9/oIji5wZ3DjzlRhnwu3eYsRbwg/CWslYw7nbCdkcgEdwR4175w uuC5l45f1FM66NEZ7BPb1LVrc7xg5uGM0J8U+pVcbsmX7Jm/hj5WjGBsqw1M2RM3bO ZtzV1br9AYFBwyS9KsO7fZ1Q8EP4XgKphPnZ+Cf4= Date: Tue, 1 Dec 2020 09:20:27 +0100 From: Greg Kroah-Hartman To: Nick Desaulniers Cc: Naresh Kamboju , linux-stable , open list , lkft-triage@lists.linaro.org, Sasha Levin , clang-built-linux , x86@vger.kernel.org, Matthias Kaehlcke Subject: Re: [stable 4.9] PANIC: double fault, error_code: 0x0 - clang boot failed on x86_64 Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Nov 30, 2020 at 12:12:39PM -0800, Nick Desaulniers wrote: > On Wed, Nov 25, 2020 at 10:38 PM Greg Kroah-Hartman > wrote: > > > > Is the mainline 4.9 tree supposed to work with clang? I didn't think > > that upstream effort started until 4.19 or so. > > (For historical records, separate from the initial bug report that > started this thread) > > I consider 785f11aa595b ("kbuild: Add better clang cross build > support") to be the starting point of a renewed effort to upstream > clang support. 785f11aa595b landed in v4.12-rc1. I think most patches > landed between there and 4.15 (would have been my guess). From there, > support was backported to 4.14, 4.9, and 4.4 for x86_64 and aarch64. > We still have CI coverage of those branches+arches with Clang today. > Pixel 2 shipped with 4.4+clang, Pixel 3 and 3a with 4.9+clang, Pixel 4 > and 4a with 4.14+clang. CrOS has also shipped clang built kernels > since 4.4+. Thanks for the info. Naresh, does this help explain why maybe testing these kernel branches with clang might not be the best thing to do? greg k-h