From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757642AbZGMXls (ORCPT ); Mon, 13 Jul 2009 19:41:48 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754551AbZGMXlr (ORCPT ); Mon, 13 Jul 2009 19:41:47 -0400 Received: from smtp1.linux-foundation.org ([140.211.169.13]:37284 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754533AbZGMXlr (ORCPT ); Mon, 13 Jul 2009 19:41:47 -0400 Date: Mon, 13 Jul 2009 16:41:43 -0700 From: Andrew Morton To: keithp@keithp.com Cc: rui.zhang@intel.com, linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org, keithp@keithp.com Subject: Re: [PATCH 1/2] acpi: don't free non-existant backlight in acpi video module Message-Id: <20090713164143.035152be.akpm@linux-foundation.org> In-Reply-To: <1247381251-27031-1-git-send-email-keithp@keithp.com> References: <1247381251-27031-1-git-send-email-keithp@keithp.com> X-Mailer: Sylpheed version 2.2.4 (GTK+ 2.8.20; i486-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > acpi: don't free non-existant backlight in acpi video module "existent" :) On Sat, 11 Jul 2009 23:47:31 -0700 keithp@keithp.com wrote: > From: Keith Packard > > acpi_video_put_one_device was attempting to remove sysfs entries and > unregister a backlight device without first checking that said backlight > device structure had been created. > > Signed-off-by: Keith Packard > --- > drivers/acpi/video.c | 7 +++++-- > 1 files changed, 5 insertions(+), 2 deletions(-) > > diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c > index 8851315..60ea984 100644 > --- a/drivers/acpi/video.c > +++ b/drivers/acpi/video.c > @@ -2004,8 +2004,11 @@ static int acpi_video_bus_put_one_device(struct acpi_video_device *device) > status = acpi_remove_notify_handler(device->dev->handle, > ACPI_DEVICE_NOTIFY, > acpi_video_device_notify); > - sysfs_remove_link(&device->backlight->dev.kobj, "device"); > - backlight_device_unregister(device->backlight); > + if (device->backlight) { > + sysfs_remove_link(&device->backlight->dev.kobj, "device"); > + backlight_device_unregister(device->backlight); > + device->backlight = NULL; > + } > if (device->cdev) { > sysfs_remove_link(&device->dev->dev.kobj, > "thermal_cooling"); um, OK. Under which circumstances was this observed? For symmetry we could instead test acpi_video_backlight_support() here. The patch assumes that someone initially zeroed device->backlight. Is that true and reliable? If so, is the memset(&device->cap, 0, sizeof(device->cap)); in acpi_video_device_find_cap() needed? Where's [patch 2/2], btw?