From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751597AbeCNTXy convert rfc822-to-8bit (ORCPT ); Wed, 14 Mar 2018 15:23:54 -0400 Received: from lilium.sigma-star.at ([109.75.188.150]:38028 "EHLO lilium.sigma-star.at" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751426AbeCNTXx (ORCPT ); Wed, 14 Mar 2018 15:23:53 -0400 From: Richard Weinberger To: Boris Brezillon Cc: Arvind Yadav , dwmw2@infradead.org, computersforpeace@gmail.com, boris.brezillon@free-electrons.com, marek.vasut@gmail.com, cyrille.pitchen@wedev4u.fr, dedekind1@gmail.com, linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/2] mtd: ubi: use put_device() if device_register fail Date: Wed, 14 Mar 2018 20:25:25 +0100 Message-ID: <3619597.KITkZyk1Wv@blindfold> In-Reply-To: <20180314195652.59b21594@bbrezillon> References: <5d9b08afdad2fbc65bac48d8ae22f4925bb80512.1520592440.git.arvind.yadav.cs@gmail.com> <20180314195652.59b21594@bbrezillon> MIME-Version: 1.0 Content-Transfer-Encoding: 8BIT Content-Type: text/plain; charset="iso-8859-1" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Am Mittwoch, 14. März 2018, 19:56:52 CET schrieb Boris Brezillon: > On Fri, 9 Mar 2018 16:20:49 +0530 > > Arvind Yadav wrote: > > if device_register() returned an error! Always use put_device() > > to give up the reference initialized. > > > > Signed-off-by: Arvind Yadav > > --- > > > > drivers/mtd/ubi/vmt.c | 1 + > > 1 file changed, 1 insertion(+) > > > > diff --git a/drivers/mtd/ubi/vmt.c b/drivers/mtd/ubi/vmt.c > > index 3fd8d7f..db85b68 100644 > > --- a/drivers/mtd/ubi/vmt.c > > +++ b/drivers/mtd/ubi/vmt.c > > @@ -609,6 +609,7 @@ int ubi_add_volume(struct ubi_device *ubi, struct > > ubi_volume *vol)> > > return err; > > > > out_cdev: > > + put_device(&vol->dev); > > > > cdev_del(&vol->cdev); > > use-after-free bug here: put_device() has freed the vol obj, and you're > dereferencing the pointer just after that. eeek, thanks for looking at more context. Arvind, while you are right that put_device() is missing, please double check that freeing the devices is also correct. Thanks, //richard