ACPI: don't free non-existent backlight in acpi video module

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>
Acked-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 5 insertions, 2 deletions

diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c
index 8851315ce858..60ea984c84a0 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");