From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755941AbcHXPXd (ORCPT ); Wed, 24 Aug 2016 11:23:33 -0400 Received: from mail.kernel.org ([198.145.29.136]:36040 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754567AbcHXPXc (ORCPT ); Wed, 24 Aug 2016 11:23:32 -0400 Date: Thu, 25 Aug 2016 00:23:19 +0900 From: Masami Hiramatsu To: Petr Mladek Cc: Jessica Yu , Masami Hiramatsu , live-patching@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: livepatch/kprobes incompatibility Message-Id: <20160825002319.43769195b85c943981d4ec8b@kernel.org> In-Reply-To: <20160824093959.GG4866@pathway.suse.cz> References: <20160824011300.GA31704@packer-debian-8-amd64.digitalocean.com> <20160824093959.GG4866@pathway.suse.cz> X-Mailer: Sylpheed 3.5.0 (GTK+ 2.24.30; x86_64-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 24 Aug 2016 11:39:59 +0200 Petr Mladek wrote: > Well, there is one more problem. We should also warn when a kprobe > is not longer accessible because the function call is redirected > by a livepatch. My last notes about it are: > > + worked on the check for lost Kprobes; decided that only Kprobe > knows about all probes and need to be informed about patching; > added KPROBE_FLAG_PATCHED and its handling; it will be used > by a fake probe that will just signalize that the function is > patched; added helper functions that will register and unregister > that fake probe; the patchset still needs some clean up before > sending I think the warning is acceptable but no need to update by flag, since the livepatch can be removed and kprobes can come back again. Moreover, at the lower level like kprobes, user might want to use it for monitoring that the patched code is actually not executed, like security inspection. Thank you, -- Masami Hiramatsu