drivers/pci/hotplug/pnv_php.c:710 pnv_php_alloc_slot() warn: address of NULL pointer 'php_slot->bus'

drivers/pci/hotplug/pnv_php.c:710 pnv_php_alloc_slot() warn: address of NULL pointer 'php_slot->bus'

[Dan Carpenter]

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   54e82e93ca93e49cb4c33988adec5c8cb9d0df31
commit: 4668619092554e1b95c9a5ac2941ca47ba6d548a PCI: pnv_php: Clean up allocated IRQs on unplug
config: powerpc64-randconfig-r071-20260104 (https://download.01.org/0day-ci/archive/20260105/202601050123.5JEZ4Znh-lkp@intel.com/config)
compiler: clang version 22.0.0git (https://github.com/llvm/llvm-project 9b8addffa70cee5b2acc5454712d9cf78ce45710)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
| Closes: https://lore.kernel.org/r/202601050123.5JEZ4Znh-lkp@intel.com/

smatch warnings:
drivers/pci/hotplug/pnv_php.c:710 pnv_php_alloc_slot() warn: address of NULL pointer 'php_slot->bus'

vim +710 drivers/pci/hotplug/pnv_php.c

66725152fb9f17b Gavin Shan      2016-05-20  678  static struct pnv_php_slot *pnv_php_alloc_slot(struct device_node *dn)
66725152fb9f17b Gavin Shan      2016-05-20  679  {
66725152fb9f17b Gavin Shan      2016-05-20  680  	struct pnv_php_slot *php_slot;
66725152fb9f17b Gavin Shan      2016-05-20  681  	struct pci_bus *bus;
66725152fb9f17b Gavin Shan      2016-05-20  682  	const char *label;
66725152fb9f17b Gavin Shan      2016-05-20  683  	uint64_t id;
39f0d6fbdc3f205 Gavin Shan      2016-09-29  684  	int ret;
66725152fb9f17b Gavin Shan      2016-05-20  685  
39f0d6fbdc3f205 Gavin Shan      2016-09-29  686  	ret = of_property_read_string(dn, "ibm,slot-label", &label);
39f0d6fbdc3f205 Gavin Shan      2016-09-29  687  	if (ret)
66725152fb9f17b Gavin Shan      2016-05-20  688  		return NULL;
66725152fb9f17b Gavin Shan      2016-05-20  689  
66725152fb9f17b Gavin Shan      2016-05-20  690  	if (pnv_pci_get_slot_id(dn, &id))
66725152fb9f17b Gavin Shan      2016-05-20  691  		return NULL;
66725152fb9f17b Gavin Shan      2016-05-20  692  
66725152fb9f17b Gavin Shan      2016-05-20  693  	bus = pci_find_bus_by_node(dn);
149ba66a90a3b3c Gavin Shan      2016-09-28  694  	if (!bus)
66725152fb9f17b Gavin Shan      2016-05-20  695  		return NULL;
66725152fb9f17b Gavin Shan      2016-05-20  696  
66725152fb9f17b Gavin Shan      2016-05-20  697  	php_slot = kzalloc(sizeof(*php_slot), GFP_KERNEL);
149ba66a90a3b3c Gavin Shan      2016-09-28  698  	if (!php_slot)
66725152fb9f17b Gavin Shan      2016-05-20  699  		return NULL;
66725152fb9f17b Gavin Shan      2016-05-20  700  
66725152fb9f17b Gavin Shan      2016-05-20  701  	php_slot->name = kstrdup(label, GFP_KERNEL);
149ba66a90a3b3c Gavin Shan      2016-09-28  702  	if (!php_slot->name) {
66725152fb9f17b Gavin Shan      2016-05-20  703  		kfree(php_slot);
66725152fb9f17b Gavin Shan      2016-05-20  704  		return NULL;
66725152fb9f17b Gavin Shan      2016-05-20  705  	}
66725152fb9f17b Gavin Shan      2016-05-20  706  
4668619092554e1 Timothy Pearson 2025-07-15  707  	/* Allocate workqueue for this slot's interrupt handling */
4668619092554e1 Timothy Pearson 2025-07-15  708  	php_slot->wq = alloc_workqueue("pciehp-%s", 0, 0, php_slot->name);
4668619092554e1 Timothy Pearson 2025-07-15  709  	if (!php_slot->wq) {
4668619092554e1 Timothy Pearson 2025-07-15 @710  		SLOT_WARN(php_slot, "Cannot alloc workqueue\n");

The SLOT_WARN() macro looks like:

#define SLOT_WARN(sl, x...) \
        ((sl)->pdev ? pci_warn((sl)->pdev, x) : dev_warn(&(sl)->bus->dev, x))

Neither ->pdev nor ->bus are set so it will crash.

4668619092554e1 Timothy Pearson 2025-07-15  711  		kfree(php_slot->name);
4668619092554e1 Timothy Pearson 2025-07-15  712  		kfree(php_slot);
4668619092554e1 Timothy Pearson 2025-07-15  713  		return NULL;
4668619092554e1 Timothy Pearson 2025-07-15  714  	}
4668619092554e1 Timothy Pearson 2025-07-15  715  
149ba66a90a3b3c Gavin Shan      2016-09-28  716  	if (dn->child && PCI_DN(dn->child))
66725152fb9f17b Gavin Shan      2016-05-20  717  		php_slot->slot_no = PCI_SLOT(PCI_DN(dn->child)->devfn);
66725152fb9f17b Gavin Shan      2016-05-20  718  	else
66725152fb9f17b Gavin Shan      2016-05-20  719  		php_slot->slot_no = -1;   /* Placeholder slot */
66725152fb9f17b Gavin Shan      2016-05-20  720  
66725152fb9f17b Gavin Shan      2016-05-20  721  	kref_init(&php_slot->kref);
66725152fb9f17b Gavin Shan      2016-05-20  722  	php_slot->state	                = PNV_PHP_STATE_INITIALIZED;
66725152fb9f17b Gavin Shan      2016-05-20  723  	php_slot->dn	                = dn;
66725152fb9f17b Gavin Shan      2016-05-20  724  	php_slot->pdev	                = bus->self;
66725152fb9f17b Gavin Shan      2016-05-20  725  	php_slot->bus	                = bus;
66725152fb9f17b Gavin Shan      2016-05-20  726  	php_slot->id	                = id;
66725152fb9f17b Gavin Shan      2016-05-20  727  	php_slot->power_state_check     = false;
66725152fb9f17b Gavin Shan      2016-05-20  728  	php_slot->slot.ops              = &php_slot_ops;
66725152fb9f17b Gavin Shan      2016-05-20  729  
66725152fb9f17b Gavin Shan      2016-05-20  730  	INIT_LIST_HEAD(&php_slot->children);
66725152fb9f17b Gavin Shan      2016-05-20  731  	INIT_LIST_HEAD(&php_slot->link);
66725152fb9f17b Gavin Shan      2016-05-20  732  
66725152fb9f17b Gavin Shan      2016-05-20  733  	return php_slot;
66725152fb9f17b Gavin Shan      2016-05-20  734  }

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki