From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-2903400-1520937552-2-9414806955318201389 X-Sieve: CMU Sieve 3.0 X-Spam-known-sender: yes ("Address greg@kroah.com in From header is in addressbook"); in-addressbook; shared/fdfaecbe-d8f0-4518-a17e-0d89bf6dc529 ("Greg") X-Spam-score: 0.0 X-Spam-hits: BAYES_00 -1.9, HEADER_FROM_DIFFERENT_DOMAINS 0.25, RCVD_IN_DNSWL_HI -5, T_RP_MATCHES_RCVD -0.01, LANGUAGES en, BAYES_USED global, SA_VERSION 3.4.0 X-Spam-source: IP='209.132.180.67', Host='vger.kernel.org', Country='CN', FromHeader='com', MailFrom='org' X-Spam-charsets: plain='us-ascii' X-Resolved-to: greg@kroah.com X-Delivered-to: greg@kroah.com X-Mail-from: stable-owner@vger.kernel.org ARC-Seal: i=1; a=rsa-sha256; cv=none; d=messagingengine.com; s=arctest; t=1520937552; b=CZ/Tn6zHAzycY9UTyL8yAXNFAGu8zanG4sTKXKHG+mOjRiu yQLZYt6HO4zPrUsO2p/dsdn836JvySJQ70erf+D34qUhGG/T9FNAaFAaSyzL5Ttq sxefruaJ6DrcDm5Ji2E6qnXPqD/HEo2a4R1s0KfgEjMTgFziJ4TK2zAdptAJnKgw pYZo4UCJOx8nYweCAegs7GAXBzfuLuimkgMeaV5IccDkRDyOl8MQxNplChTqKakf rnU0LWkoXcn6sWsENy/IoVkrwzCjGGFQ8svNoLC5xntXdqdVWP620LUd8fVGQOY4 5jm4X1iNbKjLEy7or+uBnlTE/VKHPf2rr0bXfRw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=date:from:to:cc:subject:message-id :references:mime-version:content-type:in-reply-to:sender :list-id; s=arctest; t=1520937552; bh=hkuD79qk+iomoLMVt/vuoAlaaF OIKjszAS7MWbDAYA4=; b=YQGVklh6bCmFeHluhhIXphlj+RGxdCnPtZqCIcOJga yTW+2NKUdX6g/bT/TpcawjeLO/Q0ArZ4IkKPWwui0Jch4M62/UOTCsGRzopsdeQD we1+bHDTaTEOJETPNyvMpFzdP/5YartzMY6ehi++zW9kPPpMMvltBN7OvfgQF1kJ wrU5ytylwwoxYpSqw5cW+XN72BE3L+4u3EsWD8QWGbN9xGXhVU8o9Qh9/rv8A3XI aCk3porfo4Z3D1zN/y9GJlVQm86kY0sC1BFo/MdNQon3zFSa7gpW8O0IYdyFUxiV Rm339v+MBWgSIaPzFHsdmtKPsDEecrHSfHi+daurecxA== ARC-Authentication-Results: i=1; mx4.messagingengine.com; arc=none (no signatures found); dkim=pass (2048-bit rsa key sha256) header.d=messagingengine.com header.i=@messagingengine.com header.b=RFqMWAlq x-bits=2048 x-keytype=rsa x-algorithm=sha256 x-selector=fm2; dmarc=none (p=none,has-list-id=yes,d=none) header.from=kroah.com; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-category=clean score=-100 state=0; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=kroah.com header.result=pass header_is_org_domain=yes Authentication-Results: mx4.messagingengine.com; arc=none (no signatures found); dkim=pass (2048-bit rsa key sha256) header.d=messagingengine.com header.i=@messagingengine.com header.b=RFqMWAlq x-bits=2048 x-keytype=rsa x-algorithm=sha256 x-selector=fm2; dmarc=none (p=none,has-list-id=yes,d=none) header.from=kroah.com; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-category=clean score=-100 state=0; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=kroah.com header.result=pass header_is_org_domain=yes Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932675AbeCMKin (ORCPT ); Tue, 13 Mar 2018 06:38:43 -0400 Received: from out1-smtp.messagingengine.com ([66.111.4.25]:44523 "EHLO out1-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932706AbeCMKil (ORCPT ); Tue, 13 Mar 2018 06:38:41 -0400 X-ME-Sender: Date: Tue, 13 Mar 2018 11:38:43 +0100 From: Greg KH To: Ard Biesheuvel Cc: Alex Shi , Marc Zyngier , Will Deacon , Catalin Marinas , stable@vger.kernel.org, linux-arm-kernel , Linux Kernel Mailing List Subject: Re: [PATCH 0/29] arm meltdown fix backporting review for lts 4.9 Message-ID: <20180313103843.GA29908@kroah.com> References: <1519790211-16582-1-git-send-email-alex.shi@linaro.org> <20180301152450.GA4061@kroah.com> <5cf40379-9098-da02-a471-8abd7d8f0be8@linaro.org> <20180302165415.GB8704@kroah.com> <20180313100442.GB1999@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.4 (2018-02-28) Sender: stable-owner@vger.kernel.org X-Mailing-List: stable@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: On Tue, Mar 13, 2018 at 10:13:26AM +0000, Ard Biesheuvel wrote: > On 13 March 2018 at 10:04, Greg KH wrote: > > On Wed, Mar 07, 2018 at 06:24:09PM +0000, Ard Biesheuvel wrote: > >> On 2 March 2018 at 16:54, Greg KH wrote: > >> > On Fri, Mar 02, 2018 at 05:14:50PM +0800, Alex Shi wrote: > >> >> > >> >> > >> >> On 03/01/2018 11:24 PM, Greg KH wrote: > >> >> > On Wed, Feb 28, 2018 at 11:56:22AM +0800, Alex Shi wrote: > >> >> >> Hi All, > >> >> >> > >> >> >> This backport patchset fixed the meltdown issue, it's original branch: > >> >> >> https://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git/log/?h=kpti > >> >> >> A few dependency or fixingpatches are also picked up, if they are necessary > >> >> >> and no functional changes. > >> >> >> > >> >> >> The patchset also on repository: > >> >> >> git://git.linaro.org/kernel/linux-linaro-stable.git lts-4.9-spectrevv2 > >> >> >> > >> >> >> No bug found yet from kernelci.org and lkft testing. > >> >> > > >> >> > No bugs is good, but does it actually fix the meltdown problem? What > >> >> > did you test it on? > >> >> > >> >> Oh, I have no A73/A75 cpu, so I can not reproduce meltdown bug. > >> > > >> > Then why should I trust this backport at all? > >> > > >> > Please test on the hardware that is affected, otherwise you do not know > >> > if your patches do anything or not. > >> > > >> > >> I don't think it is feasible to test these backports by confirming > >> that they make the fundamental issue go away. We simply don't have the > >> code to reproduce all the variants, and we have to rely on the > >> information provided by ARM Ltd. regarding which cores are affected > >> and which aren't. > > > > You really don't have the reproducers? Please work with ARM to resolve > > that, this should not be a non-tested set of patches. That's really > > worse than no patches at all, as if they were applied, that would > > provide a false-sense of "all is fixed". > > > > I know that on x86, the line between architecture and platform is > blurry. That is not the case on ARM, though. > > Unlike platform firmware, the OS is built on top of an abstracted > platform which is described by ARM's Architecture Reference Manual. If > ARM Ltd. issues recommendations regarding what firmware PSCI methods > to call when doing a context switch, or which barrier instruction to > issue in certain circumstances, they do so because a certain class of > hardware may require it in some cases. It is really not up to me to go > find some exploit code on GitHub, run it before and after applying the > patch and conclude that the problem is fixed. Instead, what I should > do is confirm that the changes result in the recommended actions to be > taken at the appropriate times. To _not_ take that exploit code and run it to _verify_ that your patches work, would be foolish, right? I can't believe we are having the argument of "Test that your patches actually work"... Ugh, these series are all now dropped from my patch queue until you all get your act together and get someone to verify the changes actually work. greg k-h