drivers/gpio/gpiolib.c:4732 gpiod_find_and_request() warn: 'desc' can also be NULL
From: Dan Carpenter
Date: Sat Apr 11 2026 - 04:00:44 EST
tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head: 7c6c4ed80b874f721bc7c2c937e098c56e37d2f0
commit: 1e4f6db614a310cc34d07ffbf031c76ea9581bcf gpiolib: support shared GPIOs in core subsystem code
config: x86_64-randconfig-161-20260410 (https://download.01.org/0day-ci/archive/20260411/202604110938.6uIVnQtT-lkp@xxxxxxxxx/config)
compiler: gcc-12 (Debian 12.4.0-5) 12.4.0
smatch: v0.5.0-9004-gb810ac53
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
| Fixes: 1e4f6db614a3 ("gpiolib: support shared GPIOs in core subsystem code")
| Reported-by: kernel test robot <lkp@xxxxxxxxx>
| Reported-by: Dan Carpenter <error27@xxxxxxxxx>
| Closes: https://lore.kernel.org/r/202604110938.6uIVnQtT-lkp@xxxxxxxxx/
smatch warnings:
drivers/gpio/gpiolib.c:4732 gpiod_find_and_request() warn: 'desc' can also be NULL
vim +/desc +4732 drivers/gpio/gpiolib.c
c6ccc4dde17676 Hans de Goede 2025-09-20 4643
0d776cfd5e5b55 Stephen Boyd 2024-02-22 4644 struct gpio_desc *gpiod_find_and_request(struct device *consumer,
8eb1f71e7acca4 Dmitry Torokhov 2022-11-11 4645 struct fwnode_handle *fwnode,
8eb1f71e7acca4 Dmitry Torokhov 2022-11-11 4646 const char *con_id,
8eb1f71e7acca4 Dmitry Torokhov 2022-11-11 4647 unsigned int idx,
8eb1f71e7acca4 Dmitry Torokhov 2022-11-11 4648 enum gpiod_flags flags,
8eb1f71e7acca4 Dmitry Torokhov 2022-11-11 4649 const char *label,
8eb1f71e7acca4 Dmitry Torokhov 2022-11-11 4650 bool platform_lookup_allowed)
8eb1f71e7acca4 Dmitry Torokhov 2022-11-11 4651 {
ba2dc1cb549171 Hans de Goede 2022-12-29 4652 unsigned long lookupflags = GPIO_LOOKUP_FLAGS_DEFAULT;
5c887b65bbd1a3 Andy Shevchenko 2024-03-25 4653 const char *name = function_name_or_default(con_id);
e348544f7994d2 Bartosz Golaszewski 2024-01-19 4654 /*
e348544f7994d2 Bartosz Golaszewski 2024-01-19 4655 * scoped_guard() is implemented as a for loop, meaning static
e348544f7994d2 Bartosz Golaszewski 2024-01-19 4656 * analyzers will complain about these two not being initialized.
e348544f7994d2 Bartosz Golaszewski 2024-01-19 4657 */
e348544f7994d2 Bartosz Golaszewski 2024-01-19 4658 struct gpio_desc *desc = NULL;
e348544f7994d2 Bartosz Golaszewski 2024-01-19 4659 int ret = 0;
8eb1f71e7acca4 Dmitry Torokhov 2022-11-11 4660
e348544f7994d2 Bartosz Golaszewski 2024-01-19 4661 scoped_guard(srcu, &gpio_devices_srcu) {
c6ccc4dde17676 Hans de Goede 2025-09-20 4662 desc = gpiod_fwnode_lookup(fwnode, consumer, con_id, idx,
e348544f7994d2 Bartosz Golaszewski 2024-01-19 4663 &flags, &lookupflags);
1e4f6db614a310 Bartosz Golaszewski 2025-11-12 4664 if (!IS_ERR_OR_NULL(desc) &&
Imagine desc is NULL
1e4f6db614a310 Bartosz Golaszewski 2025-11-12 4665 test_bit(GPIOD_FLAG_SHARED, &desc->flags)) {
1e4f6db614a310 Bartosz Golaszewski 2025-11-12 4666 /*
1e4f6db614a310 Bartosz Golaszewski 2025-11-12 4667 * We're dealing with a GPIO shared by multiple
1e4f6db614a310 Bartosz Golaszewski 2025-11-12 4668 * consumers. This is the moment to add the machine
1e4f6db614a310 Bartosz Golaszewski 2025-11-12 4669 * lookup table for the proxy device as previously
1e4f6db614a310 Bartosz Golaszewski 2025-11-12 4670 * we only knew the consumer's fwnode.
1e4f6db614a310 Bartosz Golaszewski 2025-11-12 4671 */
1e4f6db614a310 Bartosz Golaszewski 2025-11-12 4672 ret = gpio_shared_add_proxy_lookup(consumer, lookupflags);
1e4f6db614a310 Bartosz Golaszewski 2025-11-12 4673 if (ret)
1e4f6db614a310 Bartosz Golaszewski 2025-11-12 4674 return ERR_PTR(ret);
1e4f6db614a310 Bartosz Golaszewski 2025-11-12 4675
1e4f6db614a310 Bartosz Golaszewski 2025-11-12 4676 /* Trigger platform lookup for shared GPIO proxy. */
1e4f6db614a310 Bartosz Golaszewski 2025-11-12 4677 desc = ERR_PTR(-ENOENT);
1e4f6db614a310 Bartosz Golaszewski 2025-11-12 4678 /* Trigger it even for fwnode-only gpiod_get(). */
1e4f6db614a310 Bartosz Golaszewski 2025-11-12 4679 platform_lookup_allowed = true;
1e4f6db614a310 Bartosz Golaszewski 2025-11-12 4680 }
1e4f6db614a310 Bartosz Golaszewski 2025-11-12 4681
8eb1f71e7acca4 Dmitry Torokhov 2022-11-11 4682 if (gpiod_not_found(desc) && platform_lookup_allowed) {
8eb1f71e7acca4 Dmitry Torokhov 2022-11-11 4683 /*
e348544f7994d2 Bartosz Golaszewski 2024-01-19 4684 * Either we are not using DT or ACPI, or their lookup
1e4f6db614a310 Bartosz Golaszewski 2025-11-12 4685 * did not return a result or this is a shared GPIO. In
1e4f6db614a310 Bartosz Golaszewski 2025-11-12 4686 * that case, use platform lookup as a fallback.
8eb1f71e7acca4 Dmitry Torokhov 2022-11-11 4687 */
e348544f7994d2 Bartosz Golaszewski 2024-01-19 4688 dev_dbg(consumer,
e348544f7994d2 Bartosz Golaszewski 2024-01-19 4689 "using lookup tables for GPIO lookup\n");
8eb1f71e7acca4 Dmitry Torokhov 2022-11-11 4690 desc = gpiod_find(consumer, con_id, idx, &lookupflags);
8eb1f71e7acca4 Dmitry Torokhov 2022-11-11 4691 }
8eb1f71e7acca4 Dmitry Torokhov 2022-11-11 4692
8eb1f71e7acca4 Dmitry Torokhov 2022-11-11 4693 if (IS_ERR(desc)) {
5c887b65bbd1a3 Andy Shevchenko 2024-03-25 4694 dev_dbg(consumer, "No GPIO consumer %s found\n", name);
0eadd36d912374 Dmitry Torokhov 2022-09-03 4695 return desc;
0eadd36d912374 Dmitry Torokhov 2022-09-03 4696 }
0eadd36d912374 Dmitry Torokhov 2022-09-03 4697
8eb1f71e7acca4 Dmitry Torokhov 2022-11-11 4698 /*
8eb1f71e7acca4 Dmitry Torokhov 2022-11-11 4699 * If a connection label was passed use that, else attempt to use
8eb1f71e7acca4 Dmitry Torokhov 2022-11-11 4700 * the device name as label
8eb1f71e7acca4 Dmitry Torokhov 2022-11-11 4701 */
0eadd36d912374 Dmitry Torokhov 2022-09-03 4702 ret = gpiod_request(desc, label);
^^^^
This would crash. The zero day bot doesn't do cross function
analysis so it can't detect it.
e348544f7994d2 Bartosz Golaszewski 2024-01-19 4703 }
8eb1f71e7acca4 Dmitry Torokhov 2022-11-11 4704 if (ret) {
8eb1f71e7acca4 Dmitry Torokhov 2022-11-11 4705 if (!(ret == -EBUSY && flags & GPIOD_FLAGS_BIT_NONEXCLUSIVE))
0eadd36d912374 Dmitry Torokhov 2022-09-03 4706 return ERR_PTR(ret);
0eadd36d912374 Dmitry Torokhov 2022-09-03 4707
8eb1f71e7acca4 Dmitry Torokhov 2022-11-11 4708 /*
1e4f6db614a310 Bartosz Golaszewski 2025-11-12 4709 * This happens when there are several consumers for the same
1e4f6db614a310 Bartosz Golaszewski 2025-11-12 4710 * GPIO line: we just return here without further
1e4f6db614a310 Bartosz Golaszewski 2025-11-12 4711 * initialization. It's a hack introduced long ago to support
1e4f6db614a310 Bartosz Golaszewski 2025-11-12 4712 * fixed regulators. We now have a better solution with
1e4f6db614a310 Bartosz Golaszewski 2025-11-12 4713 * automated scanning where affected platforms just need to
1e4f6db614a310 Bartosz Golaszewski 2025-11-12 4714 * select the provided Kconfig option.
1e4f6db614a310 Bartosz Golaszewski 2025-11-12 4715 *
1e4f6db614a310 Bartosz Golaszewski 2025-11-12 4716 * FIXME: Remove the GPIOD_FLAGS_BIT_NONEXCLUSIVE flag after
1e4f6db614a310 Bartosz Golaszewski 2025-11-12 4717 * making sure all platforms use the new mechanism.
1e4f6db614a310 Bartosz Golaszewski 2025-11-12 4718 */
1e4f6db614a310 Bartosz Golaszewski 2025-11-12 4719 dev_info(consumer,
1e4f6db614a310 Bartosz Golaszewski 2025-11-12 4720 "nonexclusive access to GPIO for %s, consider updating your code to using gpio-shared-proxy\n",
1e4f6db614a310 Bartosz Golaszewski 2025-11-12 4721 name);
8eb1f71e7acca4 Dmitry Torokhov 2022-11-11 4722 return desc;
8eb1f71e7acca4 Dmitry Torokhov 2022-11-11 4723 }
8eb1f71e7acca4 Dmitry Torokhov 2022-11-11 4724
8eb1f71e7acca4 Dmitry Torokhov 2022-11-11 4725 ret = gpiod_configure_flags(desc, con_id, lookupflags, flags);
0eadd36d912374 Dmitry Torokhov 2022-09-03 4726 if (ret < 0) {
0eadd36d912374 Dmitry Torokhov 2022-09-03 4727 gpiod_put(desc);
39c9049770f8b5 Peng Fan 2024-03-25 4728 dev_err(consumer, "setup of GPIO %s failed: %d\n", name, ret);
0eadd36d912374 Dmitry Torokhov 2022-09-03 4729 return ERR_PTR(ret);
0eadd36d912374 Dmitry Torokhov 2022-09-03 4730 }
0eadd36d912374 Dmitry Torokhov 2022-09-03 4731
ee194b12bf9a2f Bartosz Golaszewski 2024-10-04 @4732 gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_REQUESTED);
0eadd36d912374 Dmitry Torokhov 2022-09-03 4733
0eadd36d912374 Dmitry Torokhov 2022-09-03 4734 return desc;
0eadd36d912374 Dmitry Torokhov 2022-09-03 4735 }
--
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