--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -4772,7 +4772,10 @@ int pci_get_new_domain_nr(void)
 void pci_bus_assign_domain_nr(struct pci_bus *bus, struct device *parent)
 {
 	static int use_dt_domains = -1;
-	int domain = of_get_pci_domain_nr(parent->of_node);
+	int domain = -1;
+
+	if (parent && parent->of_node)
+		domain = of_get_pci_domain_nr(parent->of_node);
 
 	/*
 	 * Check DT domain and use_dt_domains values.