Re: [PATCH v5 3/6] PCI: Consolidate delimiter handling into pci_dev_str_match()
From: Dan Carpenter
Date: Thu Feb 19 2026 - 02:12:18 EST
Hi Wei,
kernel test robot noticed the following build warnings:
url: https://github.com/intel-lab-lkp/linux/commits/Wei-Wang/PCI-Validate-ACS-enable-flags-against-device-specific-ACS-capabilities/20260216-103055
base: 635c467cc14ebdffab3f77610217c1dacaf88e8c
patch link: https://lore.kernel.org/r/SI2PR01MB439352E0D54243099CAAA118DC6CA%40SI2PR01MB4393.apcprd01.prod.exchangelabs.com
patch subject: [PATCH v5 3/6] PCI: Consolidate delimiter handling into pci_dev_str_match()
config: x86_64-randconfig-r072-20260216 (https://download.01.org/0day-ci/archive/20260216/202602161621.2nyGIEhM-lkp@xxxxxxxxx/config)
compiler: clang version 20.1.8 (https://github.com/llvm/llvm-project 87f0227cb60147a26a1eeb4fb06e3b505e9c7261)
smatch version: v0.5.0-8994-gd50c5a4c
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@xxxxxxxxx>
| Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
| Closes: https://lore.kernel.org/r/202602161621.2nyGIEhM-lkp@xxxxxxxxx/
smatch warnings:
drivers/pci/pci.c:430 pci_dev_str_match() warn: sscanf doesn't return error codes
vim +430 drivers/pci/pci.c
07d8d7e57c28ca Logan Gunthorpe 2018-07-30 343 /**
07d8d7e57c28ca Logan Gunthorpe 2018-07-30 344 * pci_dev_str_match - test if a string matches a device
07d8d7e57c28ca Logan Gunthorpe 2018-07-30 345 * @dev: the PCI device to test
07d8d7e57c28ca Logan Gunthorpe 2018-07-30 346 * @p: string to match the device against
40549484c434de Wei Wang 2026-02-16 347 * @endptr: pointer to the string after the match, with the delimiter skipped
07d8d7e57c28ca Logan Gunthorpe 2018-07-30 348 *
07d8d7e57c28ca Logan Gunthorpe 2018-07-30 349 * Test if a string (typically from a kernel parameter) matches a specified
07d8d7e57c28ca Logan Gunthorpe 2018-07-30 350 * PCI device. The string may be of one of the following formats:
07d8d7e57c28ca Logan Gunthorpe 2018-07-30 351 *
45db33709ccc73 Logan Gunthorpe 2018-07-30 352 * [<domain>:]<bus>:<device>.<func>[/<device>.<func>]*
07d8d7e57c28ca Logan Gunthorpe 2018-07-30 353 * pci:<vendor>:<device>[:<subvendor>:<subdevice>]
07d8d7e57c28ca Logan Gunthorpe 2018-07-30 354 *
07d8d7e57c28ca Logan Gunthorpe 2018-07-30 355 * The first format specifies a PCI bus/device/function address which
07d8d7e57c28ca Logan Gunthorpe 2018-07-30 356 * may change if new hardware is inserted, if motherboard firmware changes,
07d8d7e57c28ca Logan Gunthorpe 2018-07-30 357 * or due to changes caused in kernel parameters. If the domain is
45db33709ccc73 Logan Gunthorpe 2018-07-30 358 * left unspecified, it is taken to be 0. In order to be robust against
45db33709ccc73 Logan Gunthorpe 2018-07-30 359 * bus renumbering issues, a path of PCI device/function numbers may be used
45db33709ccc73 Logan Gunthorpe 2018-07-30 360 * to address the specific device. The path for a device can be determined
45db33709ccc73 Logan Gunthorpe 2018-07-30 361 * through the use of 'lspci -t'.
07d8d7e57c28ca Logan Gunthorpe 2018-07-30 362 *
07d8d7e57c28ca Logan Gunthorpe 2018-07-30 363 * The second format matches devices using IDs in the configuration
07d8d7e57c28ca Logan Gunthorpe 2018-07-30 364 * space which may match multiple devices in the system. A value of 0
07d8d7e57c28ca Logan Gunthorpe 2018-07-30 365 * for any field will match all devices. (Note: this differs from
07d8d7e57c28ca Logan Gunthorpe 2018-07-30 366 * in-kernel code that uses PCI_ANY_ID which is ~0; this is for
07d8d7e57c28ca Logan Gunthorpe 2018-07-30 367 * legacy reasons and convenience so users don't have to specify
07d8d7e57c28ca Logan Gunthorpe 2018-07-30 368 * FFFFFFFFs on the command line.)
07d8d7e57c28ca Logan Gunthorpe 2018-07-30 369 *
07d8d7e57c28ca Logan Gunthorpe 2018-07-30 370 * Returns 1 if the string matches the device, 0 if it does not and
07d8d7e57c28ca Logan Gunthorpe 2018-07-30 371 * a negative error code if the string cannot be parsed.
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
07d8d7e57c28ca Logan Gunthorpe 2018-07-30 372 */
07d8d7e57c28ca Logan Gunthorpe 2018-07-30 373 static int pci_dev_str_match(struct pci_dev *dev, const char *p,
07d8d7e57c28ca Logan Gunthorpe 2018-07-30 374 const char **endptr)
07d8d7e57c28ca Logan Gunthorpe 2018-07-30 375 {
07d8d7e57c28ca Logan Gunthorpe 2018-07-30 376 int ret;
45db33709ccc73 Logan Gunthorpe 2018-07-30 377 int count;
07d8d7e57c28ca Logan Gunthorpe 2018-07-30 378 unsigned short vendor, device, subsystem_vendor, subsystem_device;
07d8d7e57c28ca Logan Gunthorpe 2018-07-30 379
07d8d7e57c28ca Logan Gunthorpe 2018-07-30 380 if (strncmp(p, "pci:", 4) == 0) {
07d8d7e57c28ca Logan Gunthorpe 2018-07-30 381 /* PCI vendor/device (subvendor/subdevice) IDs are specified */
07d8d7e57c28ca Logan Gunthorpe 2018-07-30 382 p += 4;
07d8d7e57c28ca Logan Gunthorpe 2018-07-30 383 ret = sscanf(p, "%hx:%hx:%hx:%hx%n", &vendor, &device,
07d8d7e57c28ca Logan Gunthorpe 2018-07-30 384 &subsystem_vendor, &subsystem_device, &count);
07d8d7e57c28ca Logan Gunthorpe 2018-07-30 385 if (ret != 4) {
07d8d7e57c28ca Logan Gunthorpe 2018-07-30 386 ret = sscanf(p, "%hx:%hx%n", &vendor, &device, &count);
40549484c434de Wei Wang 2026-02-16 387 if (ret != 2) {
40549484c434de Wei Wang 2026-02-16 388 ret = -EINVAL;
40549484c434de Wei Wang 2026-02-16 389 goto not_found;
40549484c434de Wei Wang 2026-02-16 390 }
07d8d7e57c28ca Logan Gunthorpe 2018-07-30 391
07d8d7e57c28ca Logan Gunthorpe 2018-07-30 392 subsystem_vendor = 0;
07d8d7e57c28ca Logan Gunthorpe 2018-07-30 393 subsystem_device = 0;
07d8d7e57c28ca Logan Gunthorpe 2018-07-30 394 }
At this point ret is either 2 or 4.
07d8d7e57c28ca Logan Gunthorpe 2018-07-30 395
07d8d7e57c28ca Logan Gunthorpe 2018-07-30 396 p += count;
07d8d7e57c28ca Logan Gunthorpe 2018-07-30 397
07d8d7e57c28ca Logan Gunthorpe 2018-07-30 398 if ((!vendor || vendor == dev->vendor) &&
07d8d7e57c28ca Logan Gunthorpe 2018-07-30 399 (!device || device == dev->device) &&
07d8d7e57c28ca Logan Gunthorpe 2018-07-30 400 (!subsystem_vendor ||
07d8d7e57c28ca Logan Gunthorpe 2018-07-30 401 subsystem_vendor == dev->subsystem_vendor) &&
07d8d7e57c28ca Logan Gunthorpe 2018-07-30 402 (!subsystem_device ||
07d8d7e57c28ca Logan Gunthorpe 2018-07-30 403 subsystem_device == dev->subsystem_device))
07d8d7e57c28ca Logan Gunthorpe 2018-07-30 404 goto found;
No imagine that we don't goto found.
07d8d7e57c28ca Logan Gunthorpe 2018-07-30 405 } else {
45db33709ccc73 Logan Gunthorpe 2018-07-30 406 /*
45db33709ccc73 Logan Gunthorpe 2018-07-30 407 * PCI Bus, Device, Function IDs are specified
45db33709ccc73 Logan Gunthorpe 2018-07-30 408 * (optionally, may include a path of devfns following it)
45db33709ccc73 Logan Gunthorpe 2018-07-30 409 */
45db33709ccc73 Logan Gunthorpe 2018-07-30 410 ret = pci_dev_str_match_path(dev, p, &p);
45db33709ccc73 Logan Gunthorpe 2018-07-30 411 if (ret < 0)
40549484c434de Wei Wang 2026-02-16 412 goto not_found;
45db33709ccc73 Logan Gunthorpe 2018-07-30 413 else if (ret)
07d8d7e57c28ca Logan Gunthorpe 2018-07-30 414 goto found;
07d8d7e57c28ca Logan Gunthorpe 2018-07-30 415 }
07d8d7e57c28ca Logan Gunthorpe 2018-07-30 416
40549484c434de Wei Wang 2026-02-16 417 not_found:
40549484c434de Wei Wang 2026-02-16 418 if (ret < 0)
40549484c434de Wei Wang 2026-02-16 419 pr_err("PCI: Can't parse parameter: %s\n", p);
40549484c434de Wei Wang 2026-02-16 420
40549484c434de Wei Wang 2026-02-16 421 if (*p != ';' && *p != ',') {
40549484c434de Wei Wang 2026-02-16 422 /*
40549484c434de Wei Wang 2026-02-16 423 * End of param or invalid format. Return -ENODEV so the caller
40549484c434de Wei Wang 2026-02-16 424 * stops parsing.
40549484c434de Wei Wang 2026-02-16 425 */
40549484c434de Wei Wang 2026-02-16 426 return -ENODEV;
40549484c434de Wei Wang 2026-02-16 427 }
40549484c434de Wei Wang 2026-02-16 428
40549484c434de Wei Wang 2026-02-16 429 *endptr = p + 1;
40549484c434de Wei Wang 2026-02-16 @430 return ret;
It should return 0 here but instead it returns 2 or 4.
07d8d7e57c28ca Logan Gunthorpe 2018-07-30 431
07d8d7e57c28ca Logan Gunthorpe 2018-07-30 432 found:
40549484c434de Wei Wang 2026-02-16 433 *endptr = *p == '\0' ? p : p + 1;
07d8d7e57c28ca Logan Gunthorpe 2018-07-30 434 return 1;
07d8d7e57c28ca Logan Gunthorpe 2018-07-30 435 }
--
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