diff --git a/drivers/xen/xen-acpi-pad.c b/drivers/xen/xen-acpi-pad.c
index 75a3986..5b98e0e 100644
--- a/drivers/xen/xen-acpi-pad.c
+++ b/drivers/xen/xen-acpi-pad.c
@@ -110,9 +110,13 @@ static void acpi_pad_notify(acpi_handle handle, u32 event,
 
 static int acpi_pad_probe(struct platform_device *pdev)
 {
-	struct acpi_device *device = ACPI_COMPANION(&pdev->dev);
+	struct acpi_device *device;
 	acpi_status status;
 
+	device = ACPI_COMPANION(&pdev->dev);
+	if (!device)
+		return -ENODEV;
+
 	strcpy(acpi_device_name(device), ACPI_PROCESSOR_AGGREGATOR_DEVICE_NAME);
 	strcpy(acpi_device_class(device), ACPI_PROCESSOR_AGGREGATOR_CLASS);