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=-2.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 410C8C7618B for ; Wed, 24 Jul 2019 07:47:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 06A0421BF6 for ; Wed, 24 Jul 2019 07:47:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="ymnAVmy5" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726343AbfGXHrr (ORCPT ); Wed, 24 Jul 2019 03:47:47 -0400 Received: from merlin.infradead.org ([205.233.59.134]:53564 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725851AbfGXHrq (ORCPT ); Wed, 24 Jul 2019 03:47:46 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=abkHvxAJvwMKBCZu1/vRafgARA6Z23deu9xdjglWdiM=; b=ymnAVmy56nkJuvRLehjBGx9s/ 7CYuMmooDqv0cOw/CHYffsuX4ilCUi+CJsBWYX5Ze2WKn+RWQw70I0Q+ceLPO2hjLhWYNvwlfrpRt vdHEaWGa0kxpBV41dEEX0Rig5NU/dTZaXn/R0ZtGsAfDYSK8LVbaUxTzsJ/RWpykiksU3vEEHlZrI B9pb7TkVxtFPDKGLvWy0bCPBgRgYsEzrfKbHwKzMnsrSuTX2bquMflrBKcqdv7sZcOIHtiEpScZ3e hR7jCRFXXQFZBz/XWyBvVmQyjM4igWnkfEPWFgceoGIxz/LcdZm0QgqgbYxXLHzuU4uEPdqLamMQe iszgh61tA==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.92 #3 (Red Hat Linux)) id 1hqBzq-0001bb-2N; Wed, 24 Jul 2019 07:47:34 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id C4B4A20A5F8E5; Wed, 24 Jul 2019 09:47:32 +0200 (CEST) Date: Wed, 24 Jul 2019 09:47:32 +0200 From: Peter Zijlstra To: Josh Poimboeuf Cc: Thomas Gleixner , LKML , Nick Desaulniers , Nathan Chancellor , clang-built-linux , x86@kernel.org, Arnd Bergmann , Sedat Dilek , Linus Torvalds Subject: Re: x86 - clang / objtool status Message-ID: <20190724074732.GJ3402@hirez.programming.kicks-ass.net> References: <20190724023946.yxsz5im22fz4zxrn@treble> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190724023946.yxsz5im22fz4zxrn@treble> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jul 23, 2019 at 09:43:24PM -0500, Josh Poimboeuf wrote: > On Thu, Jul 18, 2019 at 10:40:09PM +0200, Thomas Gleixner wrote: > > > drivers/gpu/drm/i915/gem/i915_gem_execbuffer.o: warning: objtool: .altinstr_replacement+0x86: redundant UACCESS disable > > Looking at this one, I think I agree with objtool. > > PeterZ, Linus, I know y'all discussed this code a few months ago. > > __copy_from_user() already does a CLAC in its error path. So isn't the > user_access_end() redundant for the __copy_from_user() error path? Hmm, is this a result of your c705cecc8431 ("objtool: Track original function across branches") ? I'm thinking it might've 'overlooked' the CLAC in the error path before (because it didn't have a related function) and now it sees it and worries about it. Then again, I'm not seeing this warning on my GCC builds; so what's happening?