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=-6.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 44E85C48BE5 for ; Tue, 22 Jun 2021 21:34:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 28F6961075 for ; Tue, 22 Jun 2021 21:34:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230031AbhFVVhM (ORCPT ); Tue, 22 Jun 2021 17:37:12 -0400 Received: from mail.kernel.org ([198.145.29.99]:35480 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229718AbhFVVhL (ORCPT ); Tue, 22 Jun 2021 17:37:11 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id B523260FDA; Tue, 22 Jun 2021 21:34:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1624397695; bh=4cSRvAqoTHr4OwTcbZ6u9/bzZawdJvtkgTtzw7brYrQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=X7QxsBsX/81+AblHGmGihylV4H1XrwhGnCGfVW/S7hSzHRL6iM+gk6hWeUrDoskL9 46Oxnt/2JXQ/H/sHBbrh/4xuOavYBeaGtKpj5ItYX7F0GPGroX+P56uwPYgoSnFCBI Zcr1lrQSmQqqi1zHfwK3eJaIgQalJ9V7l3xSAMfI= Date: Tue, 22 Jun 2021 23:34:52 +0200 From: Greg KH To: Luis Chamberlain Cc: rafael@kernel.org, jeyu@kernel.org, ngupta@vflare.org, sergey.senozhatsky.work@gmail.com, minchan@kernel.org, axboe@kernel.dk, mbenes@suse.com, jpoimboe@redhat.com, tglx@linutronix.de, keescook@chromium.org, jikos@kernel.org, rostedt@goodmis.org, peterz@infradead.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] drivers/base/core: refcount kobject and bus on device attribute read / store Message-ID: References: <20210622210659.3708231-1-mcgrof@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210622210659.3708231-1-mcgrof@kernel.org> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jun 22, 2021 at 02:06:59PM -0700, Luis Chamberlain wrote: > static ssize_t dev_attr_show(struct kobject *kobj, struct attribute *attr, > char *buf) > { > - struct device_attribute *dev_attr = to_dev_attr(attr); > - struct device *dev = kobj_to_dev(kobj); > + struct device_attribute *dev_attr; > + struct device *dev; > + struct bus_type *bus = NULL; > ssize_t ret = -EIO; > > + dev = get_device(kobj_to_dev(kobj)); > + if (!dev) > + return ret; That check is impossible to ever hit, please recognize what things like kobj_to_dev() really are doing when calling it. thanks, greg k-h