Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762154AbXK2KFa (ORCPT ); Thu, 29 Nov 2007 05:05:30 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758503AbXK2KFX (ORCPT ); Thu, 29 Nov 2007 05:05:23 -0500 Received: from mtagate2.de.ibm.com ([195.212.29.151]:46720 "EHLO mtagate2.de.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758101AbXK2KFW (ORCPT ); Thu, 29 Nov 2007 05:05:22 -0500 Date: Thu, 29 Nov 2007 11:05:12 +0100 From: Cornelia Huck To: Alan Stern Cc: Greg KH , Kay Sievers , Kernel development list , Jonathan Corbet , Randy Dunlap Subject: Re: [PATCH] kobject: make sure kobj->ktype is set before kobject_init Message-ID: <20071129110512.02ae44e1@gondolin.boeblingen.de.ibm.com> In-Reply-To: References: <20071128214502.GA3255@kroah.com> Organization: IBM Deutschland Entwicklung GmbH Vorsitzender des Aufsichtsrats: Martin Jetter =?ISO-8859-15?Q?Gesch=E4ftsf=FChrung:?= Herbert Kircher Sitz der Gesellschaft: =?ISO-8859-15?Q?B=F6blingen?= Registergericht: Amtsgericht Stuttgart, HRB 243294 X-Mailer: Claws Mail 3.1.0 (GTK+ 2.12.1; i486-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 X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1971 Lines: 40 On Wed, 28 Nov 2007 17:00:57 -0500 (EST), Alan Stern wrote: > On Wed, 28 Nov 2007, Greg KH wrote: > > > On Wed, Nov 28, 2007 at 03:42:00PM -0500, Alan Stern wrote: > > > This patch (as1020) adds a check to kobject_init() to insure that the > > > ktype field is not NULL. This is just for safety's sake; as far as I > > > know there are no remaining places where the field is left unset. But > > > ironically, kset_init() did fail to set it! The patch fixes that and > > > removes some redundant initialization in kset_createa(). > > > > > > The patch also fixes up elevator_init(), where ktype was set after > > > calling kobject_init() instead of before. > > > > No, it's safe to set ktype after kobject_init, it was just not safe to > > set the kset. As Kay pointed out, I just added a patch to my tree to > > resolve this issue, and I'll go back and update the documentation now. > > > > I do like the "check for a ktype" warning, I'll go add that to my local > > tree and see what breaks. Odds are, all the static kobjects will :( > > You have to be careful. The ktype check I wrote lives in > kobject_init() -- that's why I had to make elevator_init() assign the > ktype before calling kobject_init(). If you put the check into > kobject_add() instead then you won't end up checking objects that get > initialized but not added. > > Yes, nobody would deliberately use a kobject without adding it, but it > could happen as the result of an failure between the _init and _add > calls. And if someone calls kobject_put() after kobject_init() to clean up, their release function will not be called if they didn't set the ktype. So the check really belongs into kobject_init() IMO. - 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/