1 files changed, 10 insertions, 3 deletions

diff --git a/arch/ia64/pci/pci.c b/arch/ia64/pci/pci.c
index d4e162d35b34..7cc3be9fa7c6 100644
--- a/arch/ia64/pci/pci.c
+++ b/arch/ia64/pci/pci.c
@@ -478,9 +478,16 @@ struct pci_bus *pci_acpi_scan_root(struct acpi_pci_root *root)
 
 int pcibios_root_bridge_prepare(struct pci_host_bridge *bridge)
 {
-        struct pci_controller *controller = bridge->bus->sysdata;
-
-        ACPI_COMPANION_SET(&bridge->dev, controller->companion);
+        /*
+         * We pass NULL as parent to pci_create_root_bus(), so if it is not NULL
+         * here, pci_create_root_bus() has been called by someone else and
+         * sysdata is likely to be different from what we expect.  Let it go in
+         * that case.
+         */
+        if (!bridge->dev.parent) {
+                struct pci_controller *controller = bridge->bus->sysdata;
+                ACPI_COMPANION_SET(&bridge->dev, controller->companion);
+        }
         return 0;
 }