[patch 6/9] acpi: don't free non-existent backlight in acpi video module

[akpm@linux-foundation.org]

From: Keith Packard <keithp@keithp.com>

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 <keithp@keithp.com>
Cc: Zhang Rui <rui.zhang@intel.com>
Cc: Len Brown <lenb@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 drivers/acpi/video.c |    7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff -puN drivers/acpi/video.c~acpi-dont-free-non-existent-backlight-in-acpi-video-module drivers/acpi/video.c
--- a/drivers/acpi/video.c~acpi-dont-free-non-existent-backlight-in-acpi-video-module
+++ a/drivers/acpi/video.c
@@ -2004,8 +2004,11 @@ static int acpi_video_bus_put_one_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");
_