ACPICA: Fix possible memory leak for Scope ASL operator

Using Scope(\) to change the scope to the root could cause a
single object memory leak.
Signed-off-by: NLin Ming <ming.m.lin@intel.com>
Signed-off-by: NBob Moore <robert.moore@intel.com>
Signed-off-by: NLen Brown <len.brown@intel.com>

drivers/acpi/acpica/dswload.c

@@ -639,26 +639,42 @@ acpi_ds_load2_begin_op(struct acpi_walk_state *walk_state,
 		break;
 
 	case AML_SCOPE_OP:
-		/*
-		 * The Path is an object reference to an existing object.
-		 * Don't enter the name into the namespace, but look it up
-		 * for use later.
-		 */
-		status =
-		    acpi_ns_lookup(walk_state->scope_info, buffer_ptr,
-				   object_type, ACPI_IMODE_EXECUTE,
-				   ACPI_NS_SEARCH_PARENT, walk_state, &(node));
-		if (ACPI_FAILURE(status)) {
-#ifdef ACPI_ASL_COMPILER
-			if (status == AE_NOT_FOUND) {
-				status = AE_OK;
-			} else {
-				ACPI_ERROR_NAMESPACE(buffer_ptr, status);
+
+		/* Special case for Scope(\) -> refers to the Root node */
+
+		if (op && (op->named.node == acpi_gbl_root_node)) {
+			node = op->named.node;
+
+			status =
+			    acpi_ds_scope_stack_push(node, object_type,
+						     walk_state);
+			if (ACPI_FAILURE(status)) {
+				return_ACPI_STATUS(status);
 			}
+		} else {
+			/*
+			 * The Path is an object reference to an existing object.
+			 * Don't enter the name into the namespace, but look it up
+			 * for use later.
+			 */
+			status =
+			    acpi_ns_lookup(walk_state->scope_info, buffer_ptr,
+					   object_type, ACPI_IMODE_EXECUTE,
+					   ACPI_NS_SEARCH_PARENT, walk_state,
+					   &(node));
+			if (ACPI_FAILURE(status)) {
+#ifdef ACPI_ASL_COMPILER
+				if (status == AE_NOT_FOUND) {
+					status = AE_OK;
+				} else {
+					ACPI_ERROR_NAMESPACE(buffer_ptr,
+							     status);
+				}
 #else
-			ACPI_ERROR_NAMESPACE(buffer_ptr, status);
+				ACPI_ERROR_NAMESPACE(buffer_ptr, status);
 #endif
-			return_ACPI_STATUS(status);
+				return_ACPI_STATUS(status);
+			}
 		}
 
 		/*