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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_2 autolearn=no 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 2C9C2C5B578 for ; Wed, 3 Jul 2019 22:57:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0B9FC20645 for ; Wed, 3 Jul 2019 22:57:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727430AbfGCW5W (ORCPT ); Wed, 3 Jul 2019 18:57:22 -0400 Received: from gate.crashing.org ([63.228.1.57]:40589 "EHLO gate.crashing.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726902AbfGCW5W (ORCPT ); Wed, 3 Jul 2019 18:57:22 -0400 Received: from localhost (localhost.localdomain [127.0.0.1]) by gate.crashing.org (8.14.1/8.14.1) with ESMTP id x63MvDeS012356; Wed, 3 Jul 2019 17:57:14 -0500 Message-ID: <319ae04497cf1982076bf801cfdf565046096fd4.camel@kernel.crashing.org> Subject: Re: [PATCH v4 OPT2] driver core: Fix use-after-free and double free on glue directory From: Benjamin Herrenschmidt To: Greg KH , Muchun Song Cc: rafael@kernel.org, prsood@codeaurora.org, mojha@codeaurora.org, gkohli@codeaurora.org, linux-kernel@vger.kernel.org Date: Thu, 04 Jul 2019 08:57:13 +1000 In-Reply-To: <20190703193606.GA8452@kroah.com> References: <20190626144021.7249-1-smuchun@gmail.com> <20190703193606.GA8452@kroah.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.28.5-0ubuntu0.18.04.1 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2019-07-03 at 21:36 +0200, Greg KH wrote: > > > -static struct kobject *get_device_parent(struct device *dev, > > - struct device *parent) > > +/** > > + * __get_device_parent() - Get the parent device kobject. > > + * @dev: Pointer to the device structure. > > + * @parent: Pointer to the parent device structure. > > + * @lock: When we live in a glue directory, should we hold the > > + * gdp_mutex lock when this function returns? If @lock > > + * is true, this function returns with the gdp_mutex > > + * holed. Otherwise it will not. > > Ugh, if you are trying to get me to hate one version of these patches, > this is how you do it :) > > A function should not "sometimes takes a lock, sometimes does not, > depending on a parameter passed into it" That way lies madness... Yes, I prefer this approach to the fix but I dont like the patch either for the same reason... ... > Anyway, this is a mess. > > Ugh I hate glue dirs... Amen... Ben.