From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756803AbcA2T34 (ORCPT ); Fri, 29 Jan 2016 14:29:56 -0500 Received: from smtprelay0236.hostedemail.com ([216.40.44.236]:55221 "EHLO smtprelay.hostedemail.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751626AbcA2T3z (ORCPT ); Fri, 29 Jan 2016 14:29:55 -0500 X-Session-Marker: 726F737465647440676F6F646D69732E6F7267 X-Spam-Summary: 2,0,0,,d41d8cd98f00b204,rostedt@goodmis.org,:::::::::::::::::::,RULES_HIT:41:355:379:541:599:800:960:973:988:989:1260:1277:1311:1313:1314:1345:1359:1437:1515:1516:1518:1534:1541:1593:1594:1711:1730:1747:1777:1792:2393:2553:2559:2562:2693:3138:3139:3140:3141:3142:3352:3622:3865:3867:3870:3871:3872:3873:3874:5007:6119:6261:7875:7903:8660:9040:10004:10400:10848:10967:11026:11232:11658:11914:12050:12517:12519:12663:12740:13069:13148:13161:13229:13230:13311:13357:14096:14097:14659:21063:21080:30012:30054:30090:30091,0,RBL:none,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:fn,MSBL:0,DNSBL:none,Custom_rules:0:0:0,LFtime:2,LUA_SUMMARY:none X-HE-Tag: pigs82_732c303b65624 X-Filterd-Recvd-Size: 2448 Date: Fri, 29 Jan 2016 14:29:50 -0500 From: Steven Rostedt To: Miroslav Benes Cc: Josh Poimboeuf , Jessica Yu , Seth Jennings , Jiri Kosina , Vojtech Pavlik , Ingo Molnar , live-patching@vger.kernel.org, linux-kernel@vger.kernel.org, Rusty Russell Subject: Re: [PATCH 1/2] livepatch: Implement separate coming and going module notifiers Message-ID: <20160129142950.0f6a6e62@gandalf.local.home> In-Reply-To: References: <1454049827-3726-1-git-send-email-jeyu@redhat.com> <1454049827-3726-2-git-send-email-jeyu@redhat.com> <20160129173010.GA19101@treble.redhat.com> <20160129124014.204020ed@gandalf.local.home> <20160129175834.GB19101@treble.redhat.com> X-Mailer: Claws Mail 3.13.1 (GTK+ 2.24.29; x86_64-pc-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 Fri, 29 Jan 2016 20:25:15 +0100 (CET) Miroslav Benes wrote: > It is possible to achieve the same goal even with the notifiers. They are > processed synchronously in complete_formation(). So we can put our klp > hook after that, right? Or better, put it to load_module() after > complete_formation() call. There is an error handling code even today > (that is, parse_args() or mod_sysfs_setup() can fail). Moreover, we'll > have a hook there with Jessica's relocation rework patch set. The problem with notifiers is that you don't know what is being called. A function call directly in the code, where it will always be needed if configured in, is a reasonable need to not use a notifier. Although, I have to admit, if live kernel patching is configured in, it's not always needed to be called here, does it? With ftrace, the call has to be done when ftrace is configured in regardless if tracing is used or not. > > But Steven's reasoning is convincing, so I'm all up for it. Great! -- Steve