root cause: when pci_devices table is empty, the pci devices will detached from DB because it's _context is None. this will leading to allocation pci devices fail, refer to: pci/stats.py
_handle_device_dependents
root cause:
when pci_devices table is empty, the pci devices will detached from DB because it's _context is None. this will leading to allocation pci devices fail, refer to: pci/stats.py
_handle_ device_ dependents