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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,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 115CFC48BE0 for ; Fri, 21 Jun 2019 13:19:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EA1ED21530 for ; Fri, 21 Jun 2019 13:19:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726368AbfFUNTh (ORCPT ); Fri, 21 Jun 2019 09:19:37 -0400 Received: from mx1.redhat.com ([209.132.183.28]:49362 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725974AbfFUNTh (ORCPT ); Fri, 21 Jun 2019 09:19:37 -0400 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id B138D4627A; Fri, 21 Jun 2019 13:19:36 +0000 (UTC) Received: from redhat.com (ovpn-121-168.rdu2.redhat.com [10.10.121.168]) by smtp.corp.redhat.com (Postfix) with ESMTPS id CCBE65D9D2; Fri, 21 Jun 2019 13:19:35 +0000 (UTC) Date: Fri, 21 Jun 2019 09:19:32 -0400 From: Joe Lawrence To: Petr Mladek Cc: Jiri Kosina , Josh Poimboeuf , Miroslav Benes , Kamalesh Babulal , Nicolai Stange , live-patching@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [RFC 0/5] livepatch: new API to track system state changes Message-ID: <20190621131932.GA20356@redhat.com> References: <20190611135627.15556-1-pmladek@suse.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190611135627.15556-1-pmladek@suse.com> User-Agent: Mutt/1.11.4 (2019-03-13) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.29]); Fri, 21 Jun 2019 13:19:36 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jun 11, 2019 at 03:56:22PM +0200, Petr Mladek wrote: > Hi, > > this is another piece in the puzzle that helps to maintain more > livepatches. > > Especially pre/post (un)patch callbacks might change a system state. > Any newly installed livepatch has to somehow deal with system state > modifications done be already installed livepatches. > > This patchset provides, hopefully, a simple and generic API that > helps to keep and pass information between the livepatches. > It is also usable to prevent loading incompatible livepatches. > Thanks for posting, Petr and aplogies for not getting to this RFC earlier. I think this strikes a reasonable balance between the (too) "simplified" versioning scheme that I posted a few weeks back, and what I was afraid might have been too complicated callback-state-version concept. This RFC reads fairly straightforward and especially easy to review given the included documentation and self-tests. I'll add a few comments per patch, but again, I like how this came out. > There was also a related idea to add a sticky flag. It should be > easy to add it later. It would perfectly fit into the new struct > klp_state. I think so, too. It would indicate that the patch is introducing a state which cannot be safely unloaded. But we can talk about that at a later time if/when we want to add that wrinkle to klp_state. -- Joe