Hi Yang, https://git-scm.com/docs/git-format-patch#_base_tree_information] url: https://github.com/intel-lab-lkp/linux/commits/Yang-Yingliang/PCI-fix-handle-error-case-in-pci_alloc_child_bus/20221028-112049 base: https://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci.git next patch link: https://lore.kernel.org/r/20221028031709.3120927-1-yangyingliang%40huawei.com patch subject: [PATCH] PCI: fix handle error case in pci_alloc_child_bus() config: x86_64-randconfig-m001 compiler: gcc-11 (Debian 11.3.0-8) 11.3.0 If you fix the issue, kindly add following tag where applicable | Reported-by: kernel test robot <lkp@xxxxxxxxx> | Reported-by: Dan Carpenter <error27@xxxxxxxxx> smatch warnings: drivers/pci/probe.c:1143 pci_alloc_child_bus() error: we previously assumed 'bridge' could be null (see line 1111) vim +/bridge +1143 drivers/pci/probe.c cbd4e055fc8f09 Adrian Bunk 2008-04-18 1076 static struct pci_bus *pci_alloc_child_bus(struct pci_bus *parent, cbd4e055fc8f09 Adrian Bunk 2008-04-18 1077 struct pci_dev *bridge, int busnr) ^1da177e4c3f41 Linus Torvalds 2005-04-16 1078 { ^1da177e4c3f41 Linus Torvalds 2005-04-16 1079 struct pci_bus *child; 07e292950b9368 Rob Herring 2020-08-20 1080 struct pci_host_bridge *host; ^1da177e4c3f41 Linus Torvalds 2005-04-16 1081 int i; 4f535093cf8f6d Yinghai Lu 2013-01-21 1082 int ret; ^1da177e4c3f41 Linus Torvalds 2005-04-16 1083 3e466e2d3a04c7 Bjorn Helgaas 2017-11-30 1084 /* Allocate a new bus and inherit stuff from the parent */ 670ba0c8883b57 Catalin Marinas 2014-09-29 1085 child = pci_alloc_bus(parent); ^1da177e4c3f41 Linus Torvalds 2005-04-16 1086 if (!child) ^1da177e4c3f41 Linus Torvalds 2005-04-16 1087 return NULL; ^1da177e4c3f41 Linus Torvalds 2005-04-16 1088 ^1da177e4c3f41 Linus Torvalds 2005-04-16 1089 child->parent = parent; ^1da177e4c3f41 Linus Torvalds 2005-04-16 1090 child->sysdata = parent->sysdata; 6e325a62a0a228 Michael S. Tsirkin 2006-02-14 1091 child->bus_flags = parent->bus_flags; ^1da177e4c3f41 Linus Torvalds 2005-04-16 1092 07e292950b9368 Rob Herring 2020-08-20 1093 host = pci_find_host_bridge(parent); 07e292950b9368 Rob Herring 2020-08-20 1094 if (host->child_ops) 07e292950b9368 Rob Herring 2020-08-20 1095 child->ops = host->child_ops; 07e292950b9368 Rob Herring 2020-08-20 1096 else 07e292950b9368 Rob Herring 2020-08-20 1097 child->ops = parent->ops; 07e292950b9368 Rob Herring 2020-08-20 1098 3e466e2d3a04c7 Bjorn Helgaas 2017-11-30 1099 /* 3e466e2d3a04c7 Bjorn Helgaas 2017-11-30 1100 * Initialize some portions of the bus device, but don't register 3e466e2d3a04c7 Bjorn Helgaas 2017-11-30 1101 * it now as the parent is not properly set up yet. fd7d1ced29e5be Greg Kroah-Hartman 2007-05-22 1102 */ fd7d1ced29e5be Greg Kroah-Hartman 2007-05-22 1103 child->dev.class = &pcibus_class; 1a9271331ab663 Kay Sievers 2008-10-30 1104 dev_set_name(&child->dev, "%04x:%02x", pci_domain_nr(child), busnr); ^1da177e4c3f41 Linus Torvalds 2005-04-16 1105 3e466e2d3a04c7 Bjorn Helgaas 2017-11-30 1106 /* Set up the primary, secondary and subordinate bus numbers */ b918c62e086b21 Yinghai Lu 2012-05-17 1107 child->number = child->busn_res.start = busnr; b918c62e086b21 Yinghai Lu 2012-05-17 1108 child->primary = parent->busn_res.start; b918c62e086b21 Yinghai Lu 2012-05-17 1109 child->busn_res.end = 0xff; ^1da177e4c3f41 Linus Torvalds 2005-04-16 1110 4f535093cf8f6d Yinghai Lu 2013-01-21 @1111 if (!bridge) { ^^^^^^ This code assumes bridge can be NULL. 4f535093cf8f6d Yinghai Lu 2013-01-21 1112 child->dev.parent = parent->bridge; 4f535093cf8f6d Yinghai Lu 2013-01-21 1113 goto add_dev; 4f535093cf8f6d Yinghai Lu 2013-01-21 1114 } 3789fa8a2e5345 Yu Zhao 2008-11-22 1115 3789fa8a2e5345 Yu Zhao 2008-11-22 1116 child->self = bridge; 3789fa8a2e5345 Yu Zhao 2008-11-22 1117 child->bridge = get_device(&bridge->dev); 4f535093cf8f6d Yinghai Lu 2013-01-21 1118 child->dev.parent = child->bridge; 98d9f30c820d50 Benjamin Herrenschmidt 2011-04-11 1119 pci_set_bus_of_node(child); 9be60ca0497a25 Matthew Wilcox 2009-12-13 1120 pci_set_bus_speed(child); 9be60ca0497a25 Matthew Wilcox 2009-12-13 1121 17e8f0d4cee2bf Gilles Buloz 2018-05-03 1122 /* 17e8f0d4cee2bf Gilles Buloz 2018-05-03 1123 * Check whether extended config space is accessible on the child 17e8f0d4cee2bf Gilles Buloz 2018-05-03 1124 * bus. Note that we currently assume it is always accessible on 17e8f0d4cee2bf Gilles Buloz 2018-05-03 1125 * the root bus. 17e8f0d4cee2bf Gilles Buloz 2018-05-03 1126 */ 17e8f0d4cee2bf Gilles Buloz 2018-05-03 1127 if (!pci_bridge_child_ext_cfg_accessible(bridge)) { 17e8f0d4cee2bf Gilles Buloz 2018-05-03 1128 child->bus_flags |= PCI_BUS_FLAGS_NO_EXTCFG; 17e8f0d4cee2bf Gilles Buloz 2018-05-03 1129 pci_info(child, "extended config space not accessible\n"); 17e8f0d4cee2bf Gilles Buloz 2018-05-03 1130 } 17e8f0d4cee2bf Gilles Buloz 2018-05-03 1131 3e466e2d3a04c7 Bjorn Helgaas 2017-11-30 1132 /* Set up default resource pointers and names */ fde09c6d8f92de Yu Zhao 2008-11-22 1133 for (i = 0; i < PCI_BRIDGE_RESOURCE_NUM; i++) { ^1da177e4c3f41 Linus Torvalds 2005-04-16 1134 child->resource[i] = &bridge->resource[PCI_BRIDGE_RESOURCES+i]; ^1da177e4c3f41 Linus Torvalds 2005-04-16 1135 child->resource[i]->name = child->name; ^1da177e4c3f41 Linus Torvalds 2005-04-16 1136 } ^1da177e4c3f41 Linus Torvalds 2005-04-16 1137 bridge->subordinate = child; ^1da177e4c3f41 Linus Torvalds 2005-04-16 1138 4f535093cf8f6d Yinghai Lu 2013-01-21 1139 add_dev: 44aa0c657e3e45 Marc Zyngier 2015-07-28 1140 pci_set_bus_msi_domain(child); 4f535093cf8f6d Yinghai Lu 2013-01-21 1141 ret = device_register(&child->dev); b1aa2ac592efcc Yang Yingliang 2022-10-28 1142 if (WARN_ON(ret < 0)) { b1aa2ac592efcc Yang Yingliang 2022-10-28 @1143 bridge->subordinate = NULL; ^^^^^^^^^^^^^^^^^^^^^^^^^^^ Unchecked dereference. b1aa2ac592efcc Yang Yingliang 2022-10-28 1144 put_device(&child->dev); b1aa2ac592efcc Yang Yingliang 2022-10-28 1145 return NULL; b1aa2ac592efcc Yang Yingliang 2022-10-28 1146 } 4f535093cf8f6d Yinghai Lu 2013-01-21 1147 10a9574756201f Jiang Liu 2013-04-12 1148 pcibios_add_bus(child); 10a9574756201f Jiang Liu 2013-04-12 1149 057bd2e0528ec6 Thierry Reding 2016-02-09 1150 if (child->ops->add_bus) { 057bd2e0528ec6 Thierry Reding 2016-02-09 1151 ret = child->ops->add_bus(child); 057bd2e0528ec6 Thierry Reding 2016-02-09 1152 if (WARN_ON(ret < 0)) 057bd2e0528ec6 Thierry Reding 2016-02-09 1153 dev_err(&child->dev, "failed to add bus: %d\n", ret); 057bd2e0528ec6 Thierry Reding 2016-02-09 1154 } 057bd2e0528ec6 Thierry Reding 2016-02-09 1155 4f535093cf8f6d Yinghai Lu 2013-01-21 1156 /* Create legacy_io and legacy_mem files for this bus */ 4f535093cf8f6d Yinghai Lu 2013-01-21 1157 pci_create_legacy_files(child); 4f535093cf8f6d Yinghai Lu 2013-01-21 1158 ^1da177e4c3f41 Linus Torvalds 2005-04-16 1159 return child; ^1da177e4c3f41 Linus Torvalds 2005-04-16 1160 } -- 0-DAY CI Kernel Test Service https://01.org/lkp
