Merge branch 'pci/dpc'

- If there's a device below a bridge, prevent a use-after-free by holding a
  reference to the device while waiting for the secondary bus to be ready
  in case the device is concurrently removed, e.g., by DPC (Lukas Wunner)

* pci/dpc:
  PCI/DPC: Fix use-after-free on concurrent DPC and hot-removal

Author: bjorn-helgaas

drivers/pci/pci.c

@@ -4823,7 +4823,7 @@ static int pci_bus_max_d3cold_delay(const struct pci_bus *bus)
  */
 int pci_bridge_wait_for_secondary_bus(struct pci_dev *dev, char *reset_type)
 {
-	struct pci_dev *child;
+	struct pci_dev *child __free(pci_dev_put) = NULL;
 	int delay;
 
 	if (pci_dev_is_disconnected(dev))
@@ -4852,8 +4852,8 @@ int pci_bridge_wait_for_secondary_bus(struct pci_dev *dev, char *reset_type)
 		return 0;
 	}
 
-	child = list_first_entry(&dev->subordinate->devices, struct pci_dev,
-				 bus_list);
+	child = pci_dev_get(list_first_entry(&dev->subordinate->devices,
+					     struct pci_dev, bus_list));
 	up_read(&pci_bus_sem);
 
 	/*