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=-13.2 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_IN_DEF_DKIM_WL 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 CF7DFC71156 for ; Tue, 1 Dec 2020 20:11:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 65E25208FE for ; Tue, 1 Dec 2020 20:11:10 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="MNqqTk+8" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2392317AbgLAUK6 (ORCPT ); Tue, 1 Dec 2020 15:10:58 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42748 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727992AbgLAUK5 (ORCPT ); Tue, 1 Dec 2020 15:10:57 -0500 Received: from mail-pg1-x541.google.com (mail-pg1-x541.google.com [IPv6:2607:f8b0:4864:20::541]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DFAA5C0617A6 for ; Tue, 1 Dec 2020 12:10:16 -0800 (PST) Received: by mail-pg1-x541.google.com with SMTP id e23so1841467pgk.12 for ; Tue, 01 Dec 2020 12:10:16 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=Tl7NwbCgPB4FUQziRcqAk5bwi9HxMdhHj333bo2TW/M=; b=MNqqTk+8wQFzYwHDIulSC0n0tpuXsS4zGpNUpp301624jzL/9+PsDGtaaaNW2AuMQo hvEXWv2j/J1rgvntkFh37d7nx4nBjCoWRtgU6s3b3mw1eJVCdLRKUHbByJbdYN3Szid5 2gn7jq7wNLxOd6WaMsugKlMP9pZkhQ29rR4SmfOU0AwFtVEWa5DH7xv9j3lGpwRTRJeJ E4zCKTiA4HBVAlTfZMML+8L4p/h1INeaUsVGALltQ5J1R2CbkfhbuUxND0SCju18LLay vCDAvEEKE6/1ND/wQ7MidfcxC7x/Exf0daMu38OzJ/UzegmheFEbcO2P3DECNu6/b0Nz ERCQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=Tl7NwbCgPB4FUQziRcqAk5bwi9HxMdhHj333bo2TW/M=; b=prZOFgsgcb8c9mBS9Tnn4SnmdRZ8qbgj91wCqCz97bgpaJqRPMxNJj7XIzZQSPtwfX jYfPIhUDR6gynDul29Zt5Amkbovv7O/b2UXHcfYQBCqaiF0VUz2MQ5CUYGF/243Lp8mS e+/u6ENPpBOY/rxAm0KY5L/E2iP+XghakxGWwwtAFc+xN3zCyQ3xjj2dNC6560uAOhp9 Qo0CGGRoh9JU+MYJDEcJiJjJofWvRtpvGFWdVnRIVE67OBhV0AlLAfwNHth2502XM/me UBoNWa1BoUfC4wnnciZJHxv2jdIOM+GhBM1jwwNCgUuzPiQmXAGACk2fBZfatWJm2JZX c58A== X-Gm-Message-State: AOAM531AocCUUta7tTDpmSRTdQ4AK9bEplyDgutKHwD7r+D/r9HNM1kD 3snqpuS4PGkW42LcMgDOJI4PUn84R89rZPtt8QA6/A== X-Google-Smtp-Source: ABdhPJye7nF810RrUIWwzBhcGCeBxTWvT8Mt1zXFoOR/zxFhAr+Msh+GI3GZYWqeCuWuT1zkuuBc54fKh9BANFQUdcA= X-Received: by 2002:a63:a902:: with SMTP id u2mr3776969pge.263.1606853416126; Tue, 01 Dec 2020 12:10:16 -0800 (PST) MIME-Version: 1.0 References: In-Reply-To: From: Nick Desaulniers Date: Tue, 1 Dec 2020 12:10:04 -0800 Message-ID: Subject: Re: [stable 4.9] PANIC: double fault, error_code: 0x0 - clang boot failed on x86_64 To: Greg Kroah-Hartman , Naresh Kamboju Cc: linux-stable , open list , lkft-triage@lists.linaro.org, Sasha Levin , clang-built-linux , x86@vger.kernel.org, Matthias Kaehlcke Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Dec 1, 2020 at 12:19 AM Greg Kroah-Hartman wrote: > > 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? On the contrary, I think it's very much worthwhile to test these branches with Clang. Particularly since CrOS is shipping x86_64 devices built with Clang since 4.4.y. This looks like a problem that's potentially been fixed but the fix not yet identified and backported. It would be good for us to identify and fix the issue before it becomes a problem for CrOS. Though, it looks like CrOS just skipped 4.9...? Looking at: https://chromium.googlesource.com/chromiumos/third_party/kernel/+refs I don't see a chromeos-4.9 branch. That said, I still find such reports helpful to track. -- Thanks, ~Nick Desaulniers