ACPI video: correct error-handling code

backlight_device_register may return an ERR_PTR
value rather than a valid pointer.

Problem found by Julia Lawall, properly fixed by Zhang Rui.

Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Acked-by: Julia Lawall <julia@diku.dk>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c
index 05dff631591c..3f685db1a76d 100644
--- a/drivers/acpi/video.c
+++ b/drivers/acpi/video.c
@@ -999,8 +999,10 @@ static void acpi_video_device_find_cap(struct acpi_video_device *device)
                 sprintf(name, "acpi_video%d", count++);
                 device->backlight = backlight_device_register(name,
                         NULL, device, &acpi_backlight_ops);
-                device->backlight->props.max_brightness = device->brightness->count-3;
                 kfree(name);
+                if (IS_ERR(device->backlight))
+                        return;
+                device->backlight->props.max_brightness = device->brightness->count-3;
 
                 result = sysfs_create_link(&device->backlight->dev.kobj,
                                            &device->dev->dev.kobj, "device");