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=-12.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 646BBC47082 for ; Tue, 8 Jun 2021 19:25:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 49DD0611BD for ; Tue, 8 Jun 2021 19:25:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235064AbhFHT1s (ORCPT ); Tue, 8 Jun 2021 15:27:48 -0400 Received: from mail.kernel.org ([198.145.29.99]:37984 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235621AbhFHTNg (ORCPT ); Tue, 8 Jun 2021 15:13:36 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id F1A156196A; Tue, 8 Jun 2021 18:49:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1623178188; bh=ckYWFdjEJXxvnkQRZWDc6jwPRd5jtBkq4BQAfKzm89Y=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=m9CxkHzhQse/6lwKnbx4+Q8tQ7/4im1G7Jtu0+HNYIQjCpgqmwJT/lxqxp41wJ0YP 9GHsQGEWuQCHlS63lKpzlgmCdPQWAJQduqHidSQo/IugO/8hClOT/n34nxAhAYmKQb tsqoEBqgLZE7kpolyeg6jlAdgqWQEVZX/wfDbycJmUwZmoUPXxEtQES1RlsB0In6nD 0KQfinqh9DKhX3rSwRHiQHOTA1wf12n4H+tUummX3fVK8+KcHyuOlu5LZZHuhCKEd+ OuFxV2EQveHvaEZMjVzOhOaZZb/AhexpxrEQJEjeJny0hGuOdB2pDkNhd4ov4PqSFC TlKfrgaqNvn3w== Subject: Re: [PATCH v3 16/16] objtool,x86: Rewrite retpoline thunk calls To: Peter Zijlstra Cc: Nick Desaulniers , =?UTF-8?B?RsSBbmctcnXDrCBTw7JuZw==?= , Josh Poimboeuf , lma@semihalf.com, Guenter Roeck , Juergen Gross , lb@semihalf.com, LKML , mbenes@suse.com, =?UTF-8?Q?Rados=c5=82aw_Biernacki?= , upstream@semihalf.com, "maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" , clang-built-linux , Sami Tolvanen References: <20210604235046.w3hazgcpsg4oefex@google.com> From: Nathan Chancellor Message-ID: <5dd58dce-c3a7-39e5-8959-b858de95b72c@kernel.org> Date: Tue, 8 Jun 2021 11:49:47 -0700 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 6/8/2021 11:17 AM, Peter Zijlstra wrote: > On Tue, Jun 08, 2021 at 10:29:56AM -0700, Nathan Chancellor wrote: >> Unfortunately, this is the VM provided by the Windows Subsystem for Linux so >> examining it is nigh-impossible :/ I am considering bisecting the transforms >> that objtool does to try and figure out the one that causes the machine to >> fail to boot or try to reproduce in a different hypervisor, unless you have >> any other ideas. > > Does breaking Windows earn points similar to breaking the binary > drivers? :-) :-) :) > The below should kill this latest transform and would quickly confirm if > the that is causing your problem. If that's not it, what was your last > known working version? Yes, that diff gets me back to booting. I will see if I can figure out the exact rewrite that blows everything up. > diff --git a/tools/objtool/check.c b/tools/objtool/check.c > index e5947fbb9e7a..d0f231b9c5a1 100644 > --- a/tools/objtool/check.c > +++ b/tools/objtool/check.c > @@ -1857,10 +1857,10 @@ static int decode_sections(struct objtool_file *file) > * Must be after add_special_section_alts(), since this will emit > * alternatives. Must be after add_{jump,call}_destination(), since > * those create the call insn lists. > - */ > ret = arch_rewrite_retpolines(file); > if (ret) > return ret; > + */ > > return 0; > } > Cheers, Nathan