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=-7.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=unavailable 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 A7F35C3A59E for ; Mon, 2 Sep 2019 17:05:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6A37D206BB for ; Mon, 2 Sep 2019 17:05:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726545AbfIBRFF (ORCPT ); Mon, 2 Sep 2019 13:05:05 -0400 Received: from mx1.redhat.com ([209.132.183.28]:36796 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726518AbfIBRFF (ORCPT ); Mon, 2 Sep 2019 13:05:05 -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 AE181301E11C; Mon, 2 Sep 2019 17:05:04 +0000 (UTC) Received: from [10.10.122.3] (ovpn-122-3.rdu2.redhat.com [10.10.122.3]) by smtp.corp.redhat.com (Postfix) with ESMTPS id F03B51001B01; Mon, 2 Sep 2019 17:05:03 +0000 (UTC) Subject: Re: [RFC PATCH 2/2] livepatch: Clear relocation targets on a module removal To: Miroslav Benes , Josh Poimboeuf Cc: Petr Mladek , jikos@kernel.org, linux-kernel@vger.kernel.org, live-patching@vger.kernel.org References: <20190719122840.15353-1-mbenes@suse.cz> <20190719122840.15353-3-mbenes@suse.cz> <20190728200427.dbrojgu7hafphia7@treble> <20190814151244.5xoaxib5iya2qjco@treble> <20190816094608.3p2z73oxcoqavnm4@pathway.suse.cz> <20190822223649.ptg6e7qyvosrljqx@treble> <20190823081306.kbkm7b4deqrare2v@pathway.suse.cz> <20190826145449.wyo7avwpqyriem46@treble> From: Joe Lawrence Message-ID: <5c649320-a9bf-ae7f-5102-483bc34d219f@redhat.com> Date: Mon, 2 Sep 2019 13:05:02 -0400 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit 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 [10.5.110.41]); Mon, 02 Sep 2019 17:05:04 +0000 (UTC) Sender: live-patching-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: live-patching@vger.kernel.org On 9/2/19 12:13 PM, Miroslav Benes wrote: >> I can easily foresee more problems like those in the future. Going >> forward we have to always keep track of which special sections are >> needed for which architectures. Those special sections can change over >> time, or can simply be overlooked for a given architecture. It's >> fragile. > > Indeed. It bothers me a lot. Even x86 "port" is not feature complete in > this regard (jump labels, alternatives,...) and who knows what lurks in > the corners of the other architectures we support. > > So it is in itself reason enough to do something about late module > patching. > Hi Miroslav, I was tinkering with the "blue-sky" ideas that I mentioned to Josh the other day. I dunno if you had a chance to look at what removing that code looks like, but I can continue to flesh out that idea if it looks interesting: https://github.com/joe-lawrence/linux/tree/blue-sky A full demo would require packaging up replacement .ko's with a livepatch, as well as "blacklisting" those deprecated .kos, etc. But that's all I had time to cook up last week before our holiday weekend here. Regards, -- Joe