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=-3.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, USER_AGENT_MUTT 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 ED9F0C43387 for ; Wed, 16 Jan 2019 19:48:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B50D120868 for ; Wed, 16 Jan 2019 19:48:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1547668126; bh=xZe+CGt3c41V9613pPP6xjUl3GhMxIM81uPuHZTg9nw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=J6Vo3I3SqCiaqJMEFdf4xKLTGd/XbegWwAkjOtY9+35cv/aKe9IwKwpjw1p4lGaBu wDiGWYHC1LGaTqITHyR8xUZD9m1sHuO1aF+oPnuC1p3aYg151HAeN1FEuOSq/IsjTU d7ewmb2nYIkBt7rJvcG5X4ldYhaIoVm2SLWryGrA= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731417AbfAPTsq (ORCPT ); Wed, 16 Jan 2019 14:48:46 -0500 Received: from mail.kernel.org ([198.145.29.99]:51580 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731174AbfAPTsq (ORCPT ); Wed, 16 Jan 2019 14:48:46 -0500 Received: from localhost (5356596B.cm-6-7b.dynamic.ziggo.nl [83.86.89.107]) (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 1D50E20675; Wed, 16 Jan 2019 19:48:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1547668124; bh=xZe+CGt3c41V9613pPP6xjUl3GhMxIM81uPuHZTg9nw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=xoQQ85LYiUY8DEbSh0isBU24W1LXjviaMEPk9kLvVJihrew1i6o0/wkmo6y81nPz2 Duhbrsf5XvBsi1ocNxnbFZY9fK+ncKrBYeFJuyfqAw2/D8/6JNmq2+tBKydyW7y8Cr 8Kx5Ede/jeJBU8YzYBI5F4iq7b2NGPagYAWN/J38= Date: Wed, 16 Jan 2019 20:48:42 +0100 From: Greg KH To: David Long Cc: Russell King - ARM Linux admin , stable@vger.kernel.org, Florian Fainelli , Julien Thierry , Tony Lindgren , Marc Zyngier , Mark Rutland , Mark Brown Subject: Re: [PATCH 4.14 00/17] V4.14 backport of more 32-bit arm spectre patches Message-ID: <20190116194842.GA7536@kroah.com> References: <20190110175150.5239-1-dave.long@linaro.org> <20190115154547.GA29144@kroah.com> <20190115163051.GA20323@kroah.com> <20190115170659.6gcgg32hpljmkzvs@e5254000004ec.dyn.armlinux.org.uk> <20190115171931.GA30853@kroah.com> <20190116193305.GA6175@kroah.com> <78d9e5e0-45cc-dd22-d34a-4a82980c772a@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <78d9e5e0-45cc-dd22-d34a-4a82980c772a@linaro.org> User-Agent: Mutt/1.11.2 (2019-01-07) Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org On Wed, Jan 16, 2019 at 02:40:10PM -0500, David Long wrote: > On 1/16/19 2:33 PM, Greg KH wrote: > > On Wed, Jan 16, 2019 at 02:27:13PM -0500, David Long wrote: > > > On 1/15/19 12:19 PM, Greg KH wrote: > > > > On Tue, Jan 15, 2019 at 05:06:59PM +0000, Russell King - ARM Linux admin wrote: > > > > > On Tue, Jan 15, 2019 at 05:30:51PM +0100, Greg KH wrote: > > > > > > On Tue, Jan 15, 2019 at 11:07:08AM -0500, David Long wrote: > > > > > > > On 1/15/19 10:45 AM, Greg KH wrote: > > > > > > > > On Thu, Jan 10, 2019 at 12:51:33PM -0500, David Long wrote: > > > > > > > > > From: "David A. Long" > > > > > > > > > > > > > > > > > > V4.14 backport of spectre patches from Russell M. King's spectre branch. > > > > > > > > > > > > > > > > If I take these, than 4.19 is vulnerable. So someone upgrading from > > > > > > > > 4.14 to 4.19 will regress :( > > > > > > > > > > > > > > > > Can you please send me a 4.19 series so I can apply that before this > > > > > > > > one? > > > > > > > > > > > > > > > > thanks, > > > > > > > > > > > > > > > > greg k-h > > > > > > > > > > > > > > > > > > > > > > > > > > > > > OK, didn't think about that being a problem. Working on it. Pretty sure > > > > > > > there's exactly one patch needed for that. > > > > > > > > > > > > one? All of these except one showed up in 4.20 and were not backported > > > > > > to 4.19 from what I can tell. The last one is in 5.0-rc1 and not even > > > > > > backported to 4.20 either, which means someone messed up and didn't tag > > > > > > it properly with a cc: stable patch :( > > > > > > > > > > > My bad, I see now I was looking at v4.20 when I made that comment, not > > > v4.19. > > > > > > > > Or they didn't think it was important enough to warrant backporting. > > > > > > > > Fair enough, then I have to ask why it's included in this series at > > > > all... > > > > > > > > > > I've been backporting all "spectre" branch patches as kept in the linux-arm > > > repo, with the assumption they're all important. If the last patch is not > > > deemed worthy of going into stable now would be a good time to declare it so > > > as I have patch sets for v4.19 and v4.9 stable versions about ready to > > > publish. > > > > Isn't it up to you to determine what is and is not important to get this > > all working properly? You are testing all of this, right? :) > > > > It is all going through kernelci and a local kvm unit test. That just tests if you didn't break anything, how are you testing that you really are mitigating the issue that you think you are fixing? What spectre-specific tests are you using to validate all of this? > The last patch in this set exists to fix a (apparently) non-critical > regression in a security patch preceding it. How worried are we about > patches to stable introducing regressions? My assumption was that this is a > bad enough thing to be fixed, but maybe not. You tell me, what is the result if that patch is not applied? Is it a bug? Performance issue? Documentation issue? Something else? I understand why it was fixed (cleanups are good to do), but you need to determine if what the cleanup is doing is actually something that matters. thanks, greg k-h