From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933062AbcFOUh6 (ORCPT ); Wed, 15 Jun 2016 16:37:58 -0400 Received: from swift.blarg.de ([78.47.110.205]:43130 "EHLO swift.blarg.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932225AbcFOUhz (ORCPT ); Wed, 15 Jun 2016 16:37:55 -0400 Date: Wed, 15 Jun 2016 22:37:53 +0200 From: Max Kellermann To: Shuah Khan Cc: linux-media@vger.kernel.org, mchehab@osg.samsung.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH 3/3] drivers/media/media-device: fix double free bug in _unregister() Message-ID: <20160615203753.GA30666@swift.blarg.de> Mail-Followup-To: Shuah Khan , linux-media@vger.kernel.org, mchehab@osg.samsung.com, linux-kernel@vger.kernel.org References: <146602170216.9818.6967531646383934202.stgit@woodpecker.blarg.de> <146602171226.9818.8828702464432665144.stgit@woodpecker.blarg.de> <5761BB4A.9040309@osg.samsung.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5761BB4A.9040309@osg.samsung.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2016/06/15 22:32, Shuah Khan wrote: > This change introduces memory leaks, since drivers are relying on > media_device_unregister() to free interfaces. This is what I thought, too, until I checked the code paths. Who adds entries to that list? Only media_gobj_create() does, and only when type==MEDIA_GRAPH_INTF_DEVNODE. That is called via media_interface_init(), via media_devnode_create(). In the whole kernel, there are two calls to media_devnode_create(): one in dvbdev.c and another one in v4l2-dev.c. Both callers take care for freeing their interface. Both would crash if somebody else would free it for them before they get a chance to do it. Which is the very thing my patch addresses. Did I miss something? Max