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=-6.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=ham 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 6FB58C433E0 for ; Wed, 13 May 2020 15:42:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8EB41206A5 for ; Wed, 13 May 2020 15:42:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1589384553; bh=c2THWjPXmYT+eNkLtJ/K4xjf95VTRhhuKD9WCsZoTzs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=CG6qHNkGpTDRpuZoEqwN836J4DHkv/WL9OiiLdBehYfudGDNC0/FZJ5DgNadaN8D4 mXxdsr/ax9lS2kVN9pcO02M/2x9YvKfYOeoH+wWODNLHQ/p5MD6Ki80jJ1mQ0TRY7L 8Ng8FwUHAlfKlaCo0EfSCaiBvx7A4OPEmExjP0FE= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730116AbgEMPmc (ORCPT ); Wed, 13 May 2020 11:42:32 -0400 Received: from mail.kernel.org ([198.145.29.99]:40472 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729539AbgEMPmc (ORCPT ); Wed, 13 May 2020 11:42:32 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (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 200DE20690; Wed, 13 May 2020 15:42:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1589384551; bh=c2THWjPXmYT+eNkLtJ/K4xjf95VTRhhuKD9WCsZoTzs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=X2q2P4hFX1QwA3UvtIli2RaL+P5gZ6EAywEiGaPU1DW6cXmwIgcS3c8YCJp5Vdoam 2oU9Z9T1rlmiDNJFt3D0DXVGp7MdWEZH9JseV7nhUsQkxRc8xU9GnXu3fpq9uEVboQ eeRvZ/V21A9seJSgI9O/eaLhy7T2/PmJ5/dySkCw= Date: Wed, 13 May 2020 17:42:28 +0200 From: Greg Kroah-Hartman To: Heikki Krogerus Cc: linux-kernel@vger.kernel.org, Naresh Kamboju , kernel test robot , Brendan Higgins , Randy Dunlap , "Rafael J. Wysocki" Subject: Re: [PATCH] kobject: Make sure the parent does not get released before its children Message-ID: <20200513154228.GC1360420@kroah.com> References: <20200513151840.36400-1-heikki.krogerus@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200513151840.36400-1-heikki.krogerus@linux.intel.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, May 13, 2020 at 06:18:40PM +0300, Heikki Krogerus wrote: > In the function kobject_cleanup(), kobject_del(kobj) is > called before the kobj->release(). That makes it possible to > release the parent of the kobject before the kobject itself. > > To fix that, adding function __kboject_del() that does > everything that kobject_del() does except release the parent > reference. kobject_cleanup() then calls __kobject_del() > instead of kobject_del(), and separately decrements the > reference count of the parent kobject after kobj->release() > has been called. > > Reported-by: Naresh Kamboju > Reported-by: kernel test robot > Fixes: 7589238a8cf3 ("Revert "software node: Simplify software_node_release() function"") > Cc: Brendan Higgins > Cc: Randy Dunlap > Suggested-by: "Rafael J. Wysocki" > Signed-off-by: Heikki Krogerus > --- > lib/kobject.c | 30 ++++++++++++++++++++---------- > 1 file changed, 20 insertions(+), 10 deletions(-) > > diff --git a/lib/kobject.c b/lib/kobject.c > index 65fa7bf70c57..32432036bef8 100644 > --- a/lib/kobject.c > +++ b/lib/kobject.c > @@ -599,14 +599,7 @@ int kobject_move(struct kobject *kobj, struct kobject *new_parent) > } > EXPORT_SYMBOL_GPL(kobject_move); > > -/** > - * kobject_del() - Unlink kobject from hierarchy. > - * @kobj: object. > - * > - * This is the function that should be called to delete an object > - * successfully added via kobject_add(). > - */ > -void kobject_del(struct kobject *kobj) > +static void __kobject_del(struct kobject *kobj) > { > struct kernfs_node *sd; > const struct kobj_type *ktype; > @@ -625,9 +618,23 @@ void kobject_del(struct kobject *kobj) > > kobj->state_in_sysfs = 0; > kobj_kset_leave(kobj); > - kobject_put(kobj->parent); > kobj->parent = NULL; > } > + > +/** > + * kobject_del() - Unlink kobject from hierarchy. > + * @kobj: object. > + * > + * This is the function that should be called to delete an object > + * successfully added via kobject_add(). > + */ > +void kobject_del(struct kobject *kobj) > +{ > + struct kobject *parent = kobj->parent; > + > + __kobject_del(kobj); > + kobject_put(parent); > +} > EXPORT_SYMBOL(kobject_del); > > /** > @@ -663,6 +670,7 @@ EXPORT_SYMBOL(kobject_get_unless_zero); > */ > static void kobject_cleanup(struct kobject *kobj) > { > + struct kobject *parent = kobj->parent; > struct kobj_type *t = get_ktype(kobj); > const char *name = kobj->name; > > @@ -684,7 +692,7 @@ static void kobject_cleanup(struct kobject *kobj) > if (kobj->state_in_sysfs) { > pr_debug("kobject: '%s' (%p): auto cleanup kobject_del\n", > kobject_name(kobj), kobj); > - kobject_del(kobj); > + __kobject_del(kobj); > } > > if (t && t->release) { > @@ -698,6 +706,8 @@ static void kobject_cleanup(struct kobject *kobj) > pr_debug("kobject: '%s': free name\n", name); > kfree_const(name); > } > + > + kobject_put(parent); > } > > #ifdef CONFIG_DEBUG_KOBJECT_RELEASE > -- > 2.26.2 > Is this the older patch we talked about before, or something else? I can't remember how we left that thread... thanks, greg k-h