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Commit 91e13aa3 authored by Aaron Lu's avatar Aaron Lu Committed by Rafael J. Wysocki
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ACPI: video: correct acpi_video_bus_add error processing 

acpi_video_bus_get_devices() may fail due to some video output device
doesn't have the _ADR method, and in this case, the error processing
is to simply free the video structure in acpi_video_bus_add(), while
leaving those already registered video output devices in the wild,
which means for some video output device, we have already registered
a backlight interface and installed a notification handler for it.
So it can happen when user is using this system, on hotkey pressing,
the notification handler will send a keycode through a non-existing
input device, causing kernel freeze.

To solve this problem, free all those already registered video output
devices once something goes wrong in acpi_video_bus_get_devices(), so
that no wild backlight interfaces and notification handlers exist.

References: https://bugzilla.kernel.org/show_bug.cgi?id=51731


Reported-and-tested-by: default avatar <i-tek@web.de>
Signed-off-by: default avatarAaron Lu <aaron.lu@intel.com>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent a6432ded

drivers/acpi/video.c

+66 −77
Original line number Diff line number Diff line
@@ -167,7 +167,8 @@ struct acpi_video_device_flags { 
	u8 dvi:1;

	u8 bios:1;

	u8 unknown:1;

	u8 reserved:2;

	u8 notify:1;

	u8 reserved:1;

};



struct acpi_video_device_cap {
@@ -1074,12 +1075,11 @@ acpi_video_bus_get_one_device(struct acpi_device *device, 
	struct acpi_video_device *data;

	struct acpi_video_device_attrib* attribute;



	if (!device || !video)

		return -EINVAL;



	status =

	    acpi_evaluate_integer(device->handle, "_ADR", NULL, &device_id);

	if (ACPI_SUCCESS(status)) {

	/* Some device omits _ADR, we skip them instead of fail */

	if (ACPI_FAILURE(status))

		return 0;



	data = kzalloc(sizeof(struct acpi_video_device), GFP_KERNEL);

	if (!data)
@@ -1117,8 +1117,7 @@ acpi_video_bus_get_one_device(struct acpi_device *device, 
			data->flags.bios = 1;

	} else {

		/* Check for legacy IDs */

			device_type = acpi_video_get_device_type(video,

								 device_id);

		device_type = acpi_video_get_device_type(video, device_id);

		/* Ignore bits 16 and 18-20 */

		switch (device_type & 0xffe2ffff) {

			case ACPI_VIDEO_DISPLAY_LEGACY_MONITOR:
@@ -1138,28 +1137,18 @@ acpi_video_bus_get_one_device(struct acpi_device *device, 
	acpi_video_device_bind(video, data);

	acpi_video_device_find_cap(data);



		status = acpi_install_notify_handler(device->handle,

						     ACPI_DEVICE_NOTIFY,

						     acpi_video_device_notify,

						     data);

		if (ACPI_FAILURE(status)) {

			printk(KERN_ERR PREFIX

					  "Error installing notify handler\n");

			if(data->brightness)

				kfree(data->brightness->levels);

			kfree(data->brightness);

			kfree(data);

			return -ENODEV;

		}

	status = acpi_install_notify_handler(device->handle, ACPI_DEVICE_NOTIFY,

					     acpi_video_device_notify, data);

	if (ACPI_FAILURE(status))

		dev_err(&device->dev, "Error installing notify handler\n");

	else

		data->flags.notify = 1;



	mutex_lock(&video->device_list_lock);

	list_add_tail(&data->entry, &video->video_device_list);

	mutex_unlock(&video->device_list_lock);



		return 0;

	}



	return -ENOENT;

	return status;

}



/*
@@ -1452,9 +1441,8 @@ acpi_video_bus_get_devices(struct acpi_video_bus *video, 


		status = acpi_video_bus_get_one_device(dev, video);

		if (status) {

			printk(KERN_WARNING PREFIX

					"Can't attach device\n");

			continue;

			dev_err(&dev->dev, "Can't attach device\n");

			break;

		}

	}

	return status;
@@ -1467,13 +1455,14 @@ static int acpi_video_bus_put_one_device(struct acpi_video_device *device) 
	if (!device || !device->video)

		return -ENOENT;



	if (device->flags.notify) {

		status = acpi_remove_notify_handler(device->dev->handle,

					    ACPI_DEVICE_NOTIFY,

					    acpi_video_device_notify);

	if (ACPI_FAILURE(status)) {

		printk(KERN_WARNING PREFIX

				ACPI_DEVICE_NOTIFY, acpi_video_device_notify);

		if (ACPI_FAILURE(status))

			dev_err(&device->dev->dev,

					"Can't remove video notify handler\n");

	}



	if (device->backlight) {

		backlight_device_unregister(device->backlight);

		device->backlight = NULL;
@@ -1755,7 +1744,7 @@ static int acpi_video_bus_add(struct acpi_device *device) 


	error = acpi_video_bus_get_devices(video, device);

	if (error)

		goto err_free_video;

		goto err_put_video;



	video->input = input = input_allocate_device();

	if (!input) {