[PATCH v5 02/10] PCI: Deprecate iomap-table functions

[Dan Carpenter]

Hi Philipp,

kernel test robot noticed the following build warnings:

https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Philipp-Stanner/PCI-Add-new-set-of-devres-functions/20240403-160932
base:   https://git.kernel.org/pub/scm/linux/kernel/git/pci/pci.git next
patch link:    https://lore.kernel.org/r/20240403080712.13986-5-pstanner%40redhat.com
patch subject: [PATCH v5 02/10] PCI: Deprecate iomap-table functions
config: i386-randconfig-141-20240404 (https://download.01.org/0day-ci/archive/20240404/202404040920.QIxhNeMu-lkp@intel.com/config)
compiler: gcc-7 (Ubuntu 7.5.0-6ubuntu2) 7.5.0

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 at intel.com>
| Reported-by: Dan Carpenter <dan.carpenter at linaro.org>
| Closes: https://lore.kernel.org/r/202404040920.QIxhNeMu-lkp@intel.com/

smatch warnings:
drivers/pci/devres.c:897 pcim_iomap_regions_request_all() error: we previously assumed 'legacy_iomap_table' could be null (see line 894)

vim +/legacy_iomap_table +897 drivers/pci/devres.c

acc2364fe66106 Philipp Stanner 2024-01-31  865  int pcim_iomap_regions_request_all(struct pci_dev *pdev, int mask,
acc2364fe66106 Philipp Stanner 2024-01-31  866  				   const char *name)
acc2364fe66106 Philipp Stanner 2024-01-31  867  {
34e90b966504f3 Philipp Stanner 2024-04-03  868  	short bar;
34e90b966504f3 Philipp Stanner 2024-04-03  869  	int ret;
34e90b966504f3 Philipp Stanner 2024-04-03  870  	void __iomem **legacy_iomap_table;
acc2364fe66106 Philipp Stanner 2024-01-31  871  
34e90b966504f3 Philipp Stanner 2024-04-03  872  	ret = pcim_request_all_regions(pdev, name);
34e90b966504f3 Philipp Stanner 2024-04-03  873  	if (ret != 0)
34e90b966504f3 Philipp Stanner 2024-04-03  874  		return ret;
acc2364fe66106 Philipp Stanner 2024-01-31  875  
34e90b966504f3 Philipp Stanner 2024-04-03  876  	for (bar = 0; bar < PCI_STD_NUM_BARS; bar++) {
34e90b966504f3 Philipp Stanner 2024-04-03  877  		if (!mask_contains_bar(mask, bar))
34e90b966504f3 Philipp Stanner 2024-04-03  878  			continue;
34e90b966504f3 Philipp Stanner 2024-04-03  879  		if (!pcim_iomap(pdev, bar, 0))
34e90b966504f3 Philipp Stanner 2024-04-03  880  			goto err;
34e90b966504f3 Philipp Stanner 2024-04-03  881  	}
34e90b966504f3 Philipp Stanner 2024-04-03  882  
34e90b966504f3 Philipp Stanner 2024-04-03  883  	return 0;
34e90b966504f3 Philipp Stanner 2024-04-03  884  
34e90b966504f3 Philipp Stanner 2024-04-03  885  err:
34e90b966504f3 Philipp Stanner 2024-04-03  886  	/*
34e90b966504f3 Philipp Stanner 2024-04-03  887  	 * Here it gets tricky: pcim_iomap() above has most likely
34e90b966504f3 Philipp Stanner 2024-04-03  888  	 * failed because it got an OOM when trying to create the
34e90b966504f3 Philipp Stanner 2024-04-03  889  	 * legacy-table.
34e90b966504f3 Philipp Stanner 2024-04-03  890  	 * We check here if that has happened. If not, pcim_iomap()
34e90b966504f3 Philipp Stanner 2024-04-03  891  	 * must have failed because of EINVAL.
34e90b966504f3 Philipp Stanner 2024-04-03  892  	 */
34e90b966504f3 Philipp Stanner 2024-04-03  893  	legacy_iomap_table = (void __iomem **)pcim_iomap_table(pdev);
34e90b966504f3 Philipp Stanner 2024-04-03 @894  	ret = legacy_iomap_table ? -EINVAL : -ENOMEM;
                                                              ^^^^^^^^^^^^^^^^^^
Check for NULL

34e90b966504f3 Philipp Stanner 2024-04-03  895  
34e90b966504f3 Philipp Stanner 2024-04-03  896  	while (--bar >= 0)
34e90b966504f3 Philipp Stanner 2024-04-03 @897  		pcim_iounmap(pdev, legacy_iomap_table[bar]);
                                                                                   ^^^^^^^^^^^^^^^^^^
Unchecked dereference

34e90b966504f3 Philipp Stanner 2024-04-03  898  
34e90b966504f3 Philipp Stanner 2024-04-03  899  	pcim_release_all_regions(pdev);
34e90b966504f3 Philipp Stanner 2024-04-03  900  
34e90b966504f3 Philipp Stanner 2024-04-03  901  	return ret;
acc2364fe66106 Philipp Stanner 2024-01-31  902  }

-- 
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https://github.com/intel/lkp-tests/wiki