From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933489AbcFQMxx (ORCPT ); Fri, 17 Jun 2016 08:53:53 -0400 Received: from nblzone-211-213.nblnetworks.fi ([83.145.211.213]:58226 "EHLO hillosipuli.retiisi.org.uk" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S932629AbcFQMxv (ORCPT ); Fri, 17 Jun 2016 08:53:51 -0400 Date: Fri, 17 Jun 2016 15:53:17 +0300 From: Sakari Ailus To: Max Kellermann Cc: linux-media@vger.kernel.org, shuahkh@osg.samsung.com, mchehab@osg.samsung.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/3] drivers/media/media-entity: clear media_gobj.mdev in _destroy() Message-ID: <20160617125317.GF24980@valkosipuli.retiisi.org.uk> References: <146602170216.9818.6967531646383934202.stgit@woodpecker.blarg.de> <146602170722.9818.9277146367995018321.stgit@woodpecker.blarg.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <146602170722.9818.9277146367995018321.stgit@woodpecker.blarg.de> 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 Hi Max, On Wed, Jun 15, 2016 at 10:15:07PM +0200, Max Kellermann wrote: > media_gobj_destroy() may be called twice on one instance - once by > media_device_unregister() and again by dvb_media_device_free(). The Is that something that should really happen, and why? The same object should not be unregistered more than once --- in many call paths gobj unregistration is followed by kfree() on the gobj. > function media_remove_intf_links() establishes and documents the > convention that mdev==NULL means that the object is not registered, > but nobody ever NULLs this variable. So this patch really implements > this behavior, and adds another mdev==NULL check to > media_gobj_destroy() to protect against double removal. > > Signed-off-by: Max Kellermann > --- > drivers/media/media-entity.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/drivers/media/media-entity.c b/drivers/media/media-entity.c > index d8a2299..9526338 100644 > --- a/drivers/media/media-entity.c > +++ b/drivers/media/media-entity.c > @@ -203,10 +203,16 @@ void media_gobj_destroy(struct media_gobj *gobj) > { > dev_dbg_obj(__func__, gobj); > > + /* Do nothing if the object is not linked. */ > + if (gobj->mdev == NULL) > + return; > + > gobj->mdev->topology_version++; > > /* Remove the object from mdev list */ > list_del(&gobj->list); > + > + gobj->mdev = NULL; > } > > int media_entity_pads_init(struct media_entity *entity, u16 num_pads, > -- Regards, Sakari Ailus e-mail: sakari.ailus@iki.fi XMPP: sailus@retiisi.org.uk