---
 drivers/acpi/acpica/nswalk.c |    3 +++
 1 file changed, 3 insertions(+)

Index: linux-pm/drivers/acpi/acpica/nswalk.c
===================================================================
--- linux-pm.orig/drivers/acpi/acpica/nswalk.c
+++ linux-pm/drivers/acpi/acpica/nswalk.c
@@ -169,6 +169,9 @@ acpi_ns_walk_namespace(acpi_object_type
 
 	if (start_node == ACPI_ROOT_OBJECT) {
 		start_node = acpi_gbl_root_node;
+		if (!start_node) {
+			return_ACPI_STATUS(AE_NO_NAMESPACE);
+		}
 	}
 
 	/* Null child means "get first node" */