Re: [PATCH v4 12/15] pinctrl: allow to mark pin functions as requestable GPIOs

[Dan Carpenter <dan.carpenter@linaro.org>]

Hi Bartosz,

kernel test robot noticed the following build warnings:

url:    https://github.com/intel-lab-lkp/linux/commits/Bartosz-Golaszewski/devres-provide-devm_kmemdup_const/20250812-170336
base:   8f5ae30d69d7543eee0d70083daf4de8fe15d585
patch link:    https://lore.kernel.org/r/20250812-pinctrl-gpio-pinfuncs-v4-12-bb3906c55e64%40linaro.org
patch subject: [PATCH v4 12/15] pinctrl: allow to mark pin functions as requestable GPIOs
config: um-randconfig-r072-20250813 (https://download.01.org/0day-ci/archive/20250813/202508132044.XYcvSpm4-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14+deb12u1) 12.2.0

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@intel.com>
| Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
| Closes: https://lore.kernel.org/r/202508132044.XYcvSpm4-lkp@intel.com/

smatch warnings:
drivers/pinctrl/pinmux.c:96 pinmux_can_be_used_for_gpio() warn: variable dereferenced before check 'desc' (see line 92)

vim +/desc +96 drivers/pinctrl/pinmux.c

7cc4e6b0e4ddf6 Andy Shevchenko     2023-11-29   88  bool pinmux_can_be_used_for_gpio(struct pinctrl_dev *pctldev, unsigned int pin)
472a61e777fe78 Stefan Wahren       2019-08-14   89  {
472a61e777fe78 Stefan Wahren       2019-08-14   90  	struct pin_desc *desc = pin_desc_get(pctldev, pin);
472a61e777fe78 Stefan Wahren       2019-08-14   91  	const struct pinmux_ops *ops = pctldev->desc->pmxops;
6dd5ffb25d7e35 Bartosz Golaszewski 2025-08-12  @92  	const struct pinctrl_setting_mux *mux_setting = desc->mux_setting;
                                                                                                        ^^^^^^^^^^^^^^^^^
Patch adds a new dereference.

6dd5ffb25d7e35 Bartosz Golaszewski 2025-08-12   93  	bool func_is_gpio = false;
472a61e777fe78 Stefan Wahren       2019-08-14   94  
472a61e777fe78 Stefan Wahren       2019-08-14   95  	/* Can't inspect pin, assume it can be used */
6ba2fd391ac58c Alexandre Torgue    2019-12-04  @96  	if (!desc || !ops)
                                                            ^^^^^
The old code assumed desc could be NULL.

472a61e777fe78 Stefan Wahren       2019-08-14   97  		return true;
472a61e777fe78 Stefan Wahren       2019-08-14   98  
5a3e85c3c397c7 Mukesh Ojha         2024-10-15   99  	guard(mutex)(&desc->mux_lock);
6dd5ffb25d7e35 Bartosz Golaszewski 2025-08-12  100  	if (mux_setting && ops->function_is_gpio)
6dd5ffb25d7e35 Bartosz Golaszewski 2025-08-12  101  		func_is_gpio = ops->function_is_gpio(pctldev, mux_setting->func);
6dd5ffb25d7e35 Bartosz Golaszewski 2025-08-12  102  
6dd5ffb25d7e35 Bartosz Golaszewski 2025-08-12  103  	if (ops->strict && desc->mux_usecount && !func_is_gpio)
472a61e777fe78 Stefan Wahren       2019-08-14  104  		return false;
472a61e777fe78 Stefan Wahren       2019-08-14  105  
472a61e777fe78 Stefan Wahren       2019-08-14  106  	return !(ops->strict && !!desc->gpio_owner);
472a61e777fe78 Stefan Wahren       2019-08-14  107  }

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