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=-7.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,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 8E40BC76191 for ; Mon, 15 Jul 2019 19:38:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 735922077A for ; Mon, 15 Jul 2019 19:38:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731242AbfGOTim (ORCPT ); Mon, 15 Jul 2019 15:38:42 -0400 Received: from mx1.redhat.com ([209.132.183.28]:39844 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730362AbfGOTij (ORCPT ); Mon, 15 Jul 2019 15:38:39 -0400 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id A955F3082A9A; Mon, 15 Jul 2019 19:38:38 +0000 (UTC) Received: from treble (ovpn-120-170.rdu2.redhat.com [10.10.120.170]) by smtp.corp.redhat.com (Postfix) with ESMTPS id CF8641001B04; Mon, 15 Jul 2019 19:38:36 +0000 (UTC) Date: Mon, 15 Jul 2019 14:38:34 -0500 From: Josh Poimboeuf To: x86@kernel.org Cc: linux-kernel@vger.kernel.org, Peter Zijlstra , Thomas Gleixner , Nick Desaulniers , Arnd Bergmann , Jann Horn , Randy Dunlap Subject: Re: [PATCH 00/22] x86, objtool: several fixes/improvements Message-ID: <20190715193834.5tvzukcwq735ufgb@treble> References: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20180716 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.45]); Mon, 15 Jul 2019 19:38:38 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Jul 14, 2019 at 07:36:55PM -0500, Josh Poimboeuf wrote: > There have been a lot of objtool bug reports lately, mainly related to > Clang and BPF. As part of fixing those bugs, I added some improvements > to objtool which uncovered yet more bugs (some kernel, some objtool). > > I've given these patches a lot of testing with both GCC and Clang. More > compile testing of objtool would be appreciated, as the kbuild test > robot doesn't seem to be paying much attention to my branches lately. > > There are still at least three outstanding issues: > > 1) With clang I see: > > drivers/gpu/drm/i915/gem/i915_gem_execbuffer.o: warning: objtool: .altinstr_replacement+0x88: redundant UACCESS disable > > I haven't dug into it yet. > > 2) There's also an issue in clang where a large switch table had a bunch > of unused (bad) entries. It's not a code correctness issue, but > hopefully it can get fixed in clang anyway. See patch 20/22 for more > details. > > 3) CONFIG_LIVEPATCH is causing some objtool "unreachable instruction" > warnings due to the new -flive-patching flag. I have some fixes > pending, but this patch set is already long enough. These patches are also at: git://git.kernel.org/pub/scm/linux/kernel/git/jpoimboe/linux.git objtool-many-fixes -- Josh