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=-9.8 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,URIBL_BLOCKED,USER_AGENT_GIT 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 85C83C433DF for ; Tue, 16 Jun 2020 15:50:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6525421501 for ; Tue, 16 Jun 2020 15:50:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592322635; bh=oXxrqKU3RYuFHlbwhWmrhjiO0p/+PyjSyNfifVE7cVI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=ZbINngQdoL7WWtuECZeyVAdnYgrBOzifwx0CnUJPISMc5djyIGM68xPQPwqOMvJiL EfC46s1l69I56jalfrk5UDFZ+G3YdQEnChUaiDuKq9ARhbxzTEVaBedHi7vjkDstao ZJCUE2Uqk4tAxrgptUYNAbBFb7zz/ec+n8cK6m4E= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732130AbgFPPud (ORCPT ); Tue, 16 Jun 2020 11:50:33 -0400 Received: from mail.kernel.org ([198.145.29.99]:46190 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732392AbgFPPuZ (ORCPT ); Tue, 16 Jun 2020 11:50:25 -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 E882720776; Tue, 16 Jun 2020 15:50:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592322624; bh=oXxrqKU3RYuFHlbwhWmrhjiO0p/+PyjSyNfifVE7cVI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=iryt4ZX8sO4ZKPeDKNeQB1Quf2irXnvhbS/KfHgN1zWPHOydQ1GRxyL514frc75uV 5eZm6eJc0WjW/69sFGDdMFU+YVSFDPvUNM/KFEnarwEX/OlLMM1D0o36TGg4vOPgj+ NLvXwhYnMSrUPDnPqw8+tovHlyrgGn602DF5bMD4= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Naresh Kamboju , kernel test robot , "Rafael J. Wysocki" , Heikki Krogerus , "Rafael J. Wysocki" , Brendan Higgins , Randy Dunlap , Sasha Levin Subject: [PATCH 5.6 041/161] kobject: Make sure the parent does not get released before its children Date: Tue, 16 Jun 2020 17:33:51 +0200 Message-Id: <20200616153108.333633206@linuxfoundation.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200616153106.402291280@linuxfoundation.org> References: <20200616153106.402291280@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Heikki Krogerus [ Upstream commit 4ef12f7198023c09ad6d25b652bd8748c965c7fa ] 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"") Suggested-by: "Rafael J. Wysocki" Signed-off-by: Heikki Krogerus Reviewed-by: Rafael J. Wysocki Reviewed-by: Brendan Higgins Tested-by: Brendan Higgins Acked-by: Randy Dunlap Link: https://lore.kernel.org/r/20200513151840.36400-1-heikki.krogerus@linux.intel.com Cc: stable Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- lib/kobject.c | 30 ++++++++++++++++++++---------- 1 file changed, 20 insertions(+), 10 deletions(-) diff --git a/lib/kobject.c b/lib/kobject.c index 83198cb37d8d..2bd631460e18 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 -- 2.25.1