PCI: Protect pci_reassign_bridge_resources() against concurrent addition/removal (fb794a70) · Commits · 戴 / test

pci_reassign_bridge_resources() can be called by pci_resize_resource() at runtime, it walks the PCI tree up and down, and it isn't currently protected against any changes or hotplug operation. Hold the pci_bus_sem to protect it. Link: https://lore.kernel.org/r/7339fd73ccaf58552737ab10008333fd9f7723f2.camel@kernel.crashing.org Signed-off-by:

drivers/pci/setup-bus.c

+7 −1

Original line number	Diff line number	Diff line
		@@ -2066,6 +2066,8 @@ int pci_reassign_bridge_resources(struct pci_dev *bridge, unsigned long type)
		unsigned int i;
		int ret;

		down_read(&pci_bus_sem);

		/* Walk to the root hub, releasing bridge BARs when possible */
		next = bridge;
		do {
		@@ -2100,8 +2102,10 @@ int pci_reassign_bridge_resources(struct pci_dev *bridge, unsigned long type)
		next = bridge->bus ? bridge->bus->self : NULL;
		} while (next);

		if (list_empty(&saved))
		if (list_empty(&saved)) {
		up_read(&pci_bus_sem);
		return -ENOENT;
		}

		__pci_bus_size_bridges(bridge->subordinate, &added);
		__pci_bridge_assign_resources(bridge, &added, &failed);
		@@ -2122,6 +2126,7 @@ int pci_reassign_bridge_resources(struct pci_dev *bridge, unsigned long type)
		}

		free_list(&saved);
		up_read(&pci_bus_sem);
		return 0;

		cleanup:
		@@ -2150,6 +2155,7 @@ cleanup:
		pci_setup_bridge(bridge->subordinate);
		}
		free_list(&saved);
		up_read(&pci_bus_sem);

		return ret;
		}