Commit af6e3def authored by Ilpo Järvinen's avatar Ilpo Järvinen Committed by Bjorn Helgaas
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PCI: WARN (not BUG()) when we fail to assign optional resources 



Resource fitting/assignment code checks if there's a remainder in
add_list (aka. realloc_head in the inner functions) using BUG_ON().
This problem typically results in a mere PCI device resource assignment
failure which does not warrant using BUG_ON(). The machine could well
come up usable even if this condition occurs because the realloc_head
relates to resources which are optional anyway.

Change BUG_ON() to WARN_ON_ONCE() and free the list if it's not empty.

[bhelgaas: subject]
Reported-by: default avatarTudor Ambarus <tudor.ambarus@linaro.org>
Signed-off-by: default avatarIlpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: default avatarKrzysztof Wilczyński <kwilczynski@kernel.org>
Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
Link: https://lore.kernel.org/linux-pci/5f103643-5e1c-43c6-b8fe-9617d3b5447c@linaro.org
Link: https://lore.kernel.org/r/20250511215223.7131-1-ilpo.jarvinen@linux.intel.com
parent 1c8a0ed2

drivers/pci/setup-bus.c

+8 −5
Original line number Diff line number Diff line
@@ -2298,8 +2298,8 @@ void pci_assign_unassigned_root_bus_resources(struct pci_bus *bus) 


		/* Depth last, allocate resources and update the hardware. */

		__pci_bus_assign_resources(bus, add_list, &fail_head);

		if (add_list)

			BUG_ON(!list_empty(add_list));

		if (WARN_ON_ONCE(add_list && !list_empty(add_list)))

			free_list(add_list);

		tried_times++;



		/* Any device complain? */
@@ -2361,7 +2361,8 @@ void pci_assign_unassigned_bridge_resources(struct pci_dev *bridge) 
		pci_bridge_distribute_available_resources(bridge, &add_list);



		__pci_bridge_assign_resources(bridge, &add_list, &fail_head);

		BUG_ON(!list_empty(&add_list));

		if (WARN_ON_ONCE(!list_empty(&add_list)))

			free_list(&add_list);

		tried_times++;



		if (list_empty(&fail_head))
@@ -2437,7 +2438,8 @@ int pci_reassign_bridge_resources(struct pci_dev *bridge, unsigned long type) 


	__pci_bus_size_bridges(bridge->subordinate, &added);

	__pci_bridge_assign_resources(bridge, &added, &failed);

	BUG_ON(!list_empty(&added));

	if (WARN_ON_ONCE(!list_empty(&added)))

		free_list(&added);



	if (!list_empty(&failed)) {

		ret = -ENOSPC;
@@ -2493,6 +2495,7 @@ void pci_assign_unassigned_bus_resources(struct pci_bus *bus) 
			__pci_bus_size_bridges(dev->subordinate, &add_list);

	up_read(&pci_bus_sem);

	__pci_bus_assign_resources(bus, &add_list, NULL);

	BUG_ON(!list_empty(&add_list));

	if (WARN_ON_ONCE(!list_empty(&add_list)))

		free_list(&add_list);

}

EXPORT_SYMBOL_GPL(pci_assign_unassigned_bus_resources);