From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp.codeaurora.org by pdx-caf-mail.web.codeaurora.org (Dovecot) with LMTP id kTT2IzKRGVvAMwAAmS7hNA ; Thu, 07 Jun 2018 20:11:31 +0000 Received: by smtp.codeaurora.org (Postfix, from userid 1000) id E3BA86074D; Thu, 7 Jun 2018 20:11:30 +0000 (UTC) Authentication-Results: smtp.codeaurora.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="G1WrFgII" X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on pdx-caf-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.9 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI,T_DKIMWL_WL_HIGH autolearn=ham autolearn_force=no version=3.4.0 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by smtp.codeaurora.org (Postfix) with ESMTP id 0C74A6063F; Thu, 7 Jun 2018 20:11:30 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 0C74A6063F Authentication-Results: pdx-caf-mail.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: pdx-caf-mail.web.codeaurora.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753185AbeFGUL2 (ORCPT + 25 others); Thu, 7 Jun 2018 16:11:28 -0400 Received: from mail.kernel.org ([198.145.29.99]:52680 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751037AbeFGUL1 (ORCPT ); Thu, 7 Jun 2018 16:11:27 -0400 Received: from localhost (LFbn-1-12247-202.w90-92.abo.wanadoo.fr [90.92.61.202]) (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 1FA3E20895; Thu, 7 Jun 2018 20:11:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1528402286; bh=5Hk6JyFDrdi19F+nO0Op9LqB8jmXdMne9xrVHreSEmg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=G1WrFgIIl0Druhy32ZKNXVdNO4+6Uden2SOopvY5FavtF834Gpqni5+q5MdbwTi9Q oMnme18p5f2xBM5BQy8RouPi879R3yUk5s8ELOnd+VpfWwkH+wPNL3J8BrT73yT72n Ga2YK2MlVYr8pOA0I09kfW6I7DPUPUiJWxB02FHY= Date: Thu, 7 Jun 2018 22:11:02 +0200 From: Greg KH To: Nick Desaulniers Cc: Josh Poimboeuf , Matthias Kaehlcke , Ingo Molnar , Peter Zijlstra , Linus Torvalds , LKML , Thomas Gleixner , Andrew Morton , James Y Knight , Chandler Carruth , Stephen Hines , Kees Cook , groeck@chromium.org, Greg Hackmann Subject: Re: [GIT PULL] x86/build changes for v4.17 Message-ID: <20180607201102.GA6844@kroah.com> References: <20180402095033.nfzcrmxvpm46dhbl@gmail.com> <20180403085904.GY4082@hirez.programming.kicks-ass.net> <20180403095118.rpf7tj577dppvx7d@gmail.com> <20180403180658.GE87376@google.com> <20180404093823.GC25996@kroah.com> <20180404193247.lsoxe3xjcidwtlgv@treble> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.0 (2018-05-17) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jun 07, 2018 at 12:23:31PM -0700, Nick Desaulniers wrote: > On Wed, Apr 4, 2018 at 12:32 PM Josh Poimboeuf wrote: > > > > On Wed, Apr 04, 2018 at 04:53:52PM +0000, Nick Desaulniers wrote: > > > (re-sending as plain text) > > > > > > On Wed, Apr 4, 2018 at 2:38 AM Greg KH wrote: > > > > There are known-bugs with building a kernel with clang right now (I > > > > pointed one out a few days ago about NULL checks being deleted from the > > > > clang output for no good reason, which really is scary for obvious > > > > reasons). > > > > > > Is this the thread you are referring to? > > > https://lkml.org/lkml/2018/3/27/1286 > > > > > > It's definitely something curious that I'll need to sit down and > > > investigate more. If there are other known instances, it would be good to > > > let me know. > > > > As Matthias mentioned elsewhere, it sounds like they're planning to > > implement -fno-delete-null-pointer-checks, which would presumably fix > > the above issue. > > Just to follow this up, -fno-delete-null-pointer-checks is being added > to clang in: > https://reviews.llvm.org/D47894 > https://reviews.llvm.org/D47895 That's great news, thanks for letting us know. greg k-h