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=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no 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 177E1ECE588 for ; Tue, 15 Oct 2019 15:31:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DF3E42086A for ; Tue, 15 Oct 2019 15:31:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1571153494; bh=/yZECSqFbWBM+e6pr6Kd5FtztUG0bQpf7Ebo3eMkr4Y=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=PVO6U7gaz6kdPf3/SM7ji9Dqy6QZNQoTnCMDVVQfsp1YQX44hNWGKwwnyBIirOonO zczkXhr89XPM+DeS26BKZFGJZwV4l+1J5iIrdpgOBWGz2WwyrbXA6Wn5SVzZKZ8tYp mCSrgEE7C4CMm4lDIPXXiiEVsHHHf2nBN4n2n0JA= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387547AbfJOPbd (ORCPT ); Tue, 15 Oct 2019 11:31:33 -0400 Received: from mail.kernel.org ([198.145.29.99]:58800 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1733265AbfJOPbd (ORCPT ); Tue, 15 Oct 2019 11:31:33 -0400 Received: from linux-8ccs (ip5f5adbbb.dynamic.kabel-deutschland.de [95.90.219.187]) (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 C2A7E20640; Tue, 15 Oct 2019 15:31:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1571153492; bh=/yZECSqFbWBM+e6pr6Kd5FtztUG0bQpf7Ebo3eMkr4Y=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=qpniGNXnqcLyiiO/RRW9XTnDa4FejS5RQpnNbcvdVBprpweRnstkoVNPSM186i3u/ QvNSUgmnGm0gkq1WLc4rTyy0xdwNki9GMlO2aJoeh7T3IcdReTIB9KQyAvAAIte9xL Jo47KrGF4zgd9S3rbMzlmswUUXphuGOtdQQQ5I8c= Date: Tue, 15 Oct 2019 17:31:20 +0200 From: Jessica Yu To: Joe Lawrence Cc: Miroslav Benes , Peter Zijlstra , Steven Rostedt , x86@kernel.org, linux-kernel@vger.kernel.org, mhiramat@kernel.org, bristot@redhat.com, jbaron@akamai.com, torvalds@linux-foundation.org, tglx@linutronix.de, mingo@kernel.org, namit@vmware.com, hpa@zytor.com, luto@kernel.org, ard.biesheuvel@linaro.org, jpoimboe@redhat.com, live-patching@vger.kernel.org Subject: Re: [PATCH v3 5/6] x86/ftrace: Use text_poke() Message-ID: <20191015153120.GA21580@linux-8ccs> References: <20191010092054.GR2311@hirez.programming.kicks-ass.net> <20191010091956.48fbcf42@gandalf.local.home> <20191010140513.GT2311@hirez.programming.kicks-ass.net> <20191010115449.22044b53@gandalf.local.home> <20191010172819.GS2328@hirez.programming.kicks-ass.net> <20191011125903.GN2359@hirez.programming.kicks-ass.net> <20191015130739.GA23565@linux-8ccs> <20191015135634.GK2328@hirez.programming.kicks-ass.net> <88bab814-ea24-ece9-2bc0-7a1e10a62f12@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: <88bab814-ea24-ece9-2bc0-7a1e10a62f12@redhat.com> X-OS: Linux linux-8ccs 4.12.14-lp150.12.28-default x86_64 User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org +++ Joe Lawrence [15/10/19 11:06 -0400]: >On 10/15/19 10:13 AM, Miroslav Benes wrote: >>Yes, it does. klp_module_coming() calls module_disable_ro() on all >>patching modules which patch the coming module in order to call >>apply_relocate_add(). New (patching) code for a module can be relocated >>only when the relevant module is loaded. > >FWIW, would the LPC blue-sky2 model (ie, Steve's suggestion @ >plumber's where livepatches only patch a single object and updates are >kept on disk to handle coming module updates as they are loaded) >eliminate those outstanding relocations and the need to perform this >late permission flipping? I wasn't at Plumbers sadly, was this idea documented/talked about in detail somewhere? (recording, slides, etherpad, etc?). What do you mean by updates are kept on disk? Maybe someone can explain it more in detail? :)