Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754147AbbBJT5N (ORCPT ); Tue, 10 Feb 2015 14:57:13 -0500 Received: from mx1.redhat.com ([209.132.183.28]:55317 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753787AbbBJT5L (ORCPT ); Tue, 10 Feb 2015 14:57:11 -0500 Date: Tue, 10 Feb 2015 13:57:06 -0600 From: Josh Poimboeuf To: Jiri Slaby Cc: Seth Jennings , Jiri Kosina , Vojtech Pavlik , Masami Hiramatsu , live-patching@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH 8/9] livepatch: allow patch modules to be removed Message-ID: <20150210195706.GB1118@treble.redhat.com> References: <5a1f98566264a40895704d553e9acf8cfda0659c.1423499826.git.jpoimboe@redhat.com> <54DA55CA.3080408@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <54DA55CA.3080408@suse.cz> User-Agent: Mutt/1.5.23.1-rc1 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1432 Lines: 36 On Tue, Feb 10, 2015 at 08:02:34PM +0100, Jiri Slaby wrote: > On 02/09/2015, 06:31 PM, Josh Poimboeuf wrote: > > --- a/kernel/livepatch/core.c > > +++ b/kernel/livepatch/core.c > ... > > @@ -497,10 +500,6 @@ static struct attribute *klp_patch_attrs[] = { > > > > static void klp_kobj_release_patch(struct kobject *kobj) > > { > > - /* > > - * Once we have a consistency model we'll need to module_put() the > > - * patch module here. See klp_register_patch() for more details. > > - */ > > I deliberately let you write the note in there :). What happens when I > leave some attribute in /sys open and you remove the module in the meantime? You're right, as was I the first time :-) The only problem is that it would be nice if we could call klp_unregister_patch() from the patch module's exit function, so that doing an rmmod on the patch module unregisters it. But if we put module_put() in the patch release function, then we have a circular dependency and we could never rmmod it. How about instead we do a klp_is_patch_registered() at the beginning of all the attribute accessor functions? It's kind of ugly, but I can't think of a better idea at the moment. -- Josh -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/