[PATCH 2/4] ACPI: video - fix potential crash when unloading

[Dmitry Torokhov <dmitry.torokhov@gmail.com>]

thermal_cooling_device_register() returns error encoded in a pointer
when it fails in which case we need to explictly set device->cdev
to NULL so we don't try to unregister it when unloading.

Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
---

 drivers/acpi/video.c |   12 +++++++++++-
 1 files changed, 11 insertions(+), 1 deletions(-)

diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c
index d8e64cf..98ade4e 100644
--- a/drivers/acpi/video.c
+++ b/drivers/acpi/video.c
@@ -992,8 +992,18 @@ static void acpi_video_device_find_cap(struct acpi_video_device *device)
 
 		device->cdev = thermal_cooling_device_register("LCD",
 					device->dev, &video_cooling_ops);
-		if (IS_ERR(device->cdev))
+		if (IS_ERR(device->cdev)) {
+			/*
+			 * Set cdev to NULL so we don't crash trying to
+			 * free it.
+			 * Also, why the hell we are returnign early and
+			 * not attempt to register video output if cooling
+			 * device registration failed?
+			 * -- dtor
+			 */
+			device->cdev = NULL;
 			return;
+		}
 
 		dev_info(&device->dev->dev, "registered as cooling_device%d\n",
 			 device->cdev->id);