From af6e3defb11a1c67cd462485655b43b5d70524b1 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Ilpo=20J=C3=A4rvinen?= Date: Mon, 12 May 2025 00:52:23 +0300 Subject: [PATCH] PCI: WARN (not BUG()) when we fail to assign optional resources MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit 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: Tudor Ambarus Signed-off-by: Ilpo Järvinen Signed-off-by: Krzysztof Wilczyński Signed-off-by: Bjorn Helgaas 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 --- drivers/pci/setup-bus.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c index 54d6f4fa3ce16..a0d815557f5cf 100644 --- a/drivers/pci/setup-bus.c +++ b/drivers/pci/setup-bus.c @@ -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); -- 2.39.5