diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index f1a5da4..fea6f8d 100644
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -958,6 +958,9 @@
 		return -EINVAL;
 	}
 
+	if (!dev)
+		return -EINVAL;
+
 	dev->cpu = pr->id;
 
 	if (max_cstate == 0)