linux-kernel - Re: [PATCH 3/3] [PATCH v6] leds: Add LED1202 I2C driver

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Message-ID: <954d6aa4-5dc7-4421-9b92-4cb9a0b9d40c@suswa.mountain>
Date: Fri, 8 Nov 2024 17:34:01 +0300
From: Dan Carpenter <dan.carpenter@...aro.org>
To: oe-kbuild@...ts.linux.dev,
	Vicentiu Galanopulo <vicentiu.galanopulo@...ote-tech.co.uk>,
	Pavel Machek <pavel@....cz>, Lee Jones <lee@...nel.org>,
	Rob Herring <robh@...nel.org>,
	Krzysztof Kozlowski <krzk@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>,
	Jonathan Corbet <corbet@....net>, linux-leds@...r.kernel.org,
	devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-doc@...r.kernel.org
Cc: lkp@...el.com, oe-kbuild-all@...ts.linux.dev
Subject: Re: [PATCH 3/3] [PATCH v6] leds: Add LED1202 I2C driver

Hi Vicentiu,

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/Vicentiu-Galanopulo/dt-bindings-leds-Add-LED1202-LED-Controller/20241106-142011
base:   https://git.kernel.org/pub/scm/linux/kernel/git/lee/leds.git for-leds-next
patch link:    https://lore.kernel.org/r/20241106061812.6819-3-vicentiu.galanopulo%40remote-tech.co.uk
patch subject: [PATCH 3/3] [PATCH v6] leds: Add LED1202 I2C driver
config: loongarch-randconfig-r073-20241107 (https://download.01.org/0day-ci/archive/20241108/202411080756.6eYdrM5X-lkp@intel.com/config)
compiler: loongarch64-linux-gcc (GCC) 14.2.0

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@...el.com>
| Reported-by: Dan Carpenter <dan.carpenter@...aro.org>
| Closes: https://lore.kernel.org/r/202411080756.6eYdrM5X-lkp@intel.com/

smatch warnings:
drivers/leds/leds-st1202.c:175 st1202_brightness_get() error: uninitialized symbol 'value'.

vim +/value +175 drivers/leds/leds-st1202.c

7e6780184dc934 Vicentiu Galanopulo 2024-11-06  155  static enum led_brightness st1202_brightness_get(struct led_classdev *led_cdev)
7e6780184dc934 Vicentiu Galanopulo 2024-11-06  156  {
7e6780184dc934 Vicentiu Galanopulo 2024-11-06  157  	struct st1202_led *led;
7e6780184dc934 Vicentiu Galanopulo 2024-11-06  158  	struct st1202_chip *chip;
7e6780184dc934 Vicentiu Galanopulo 2024-11-06  159  	u8 value;
7e6780184dc934 Vicentiu Galanopulo 2024-11-06  160  	int ret;
7e6780184dc934 Vicentiu Galanopulo 2024-11-06  161  
7e6780184dc934 Vicentiu Galanopulo 2024-11-06  162  	led = cdev_to_st1202_led(led_cdev);
7e6780184dc934 Vicentiu Galanopulo 2024-11-06  163  	chip = led->chip;
7e6780184dc934 Vicentiu Galanopulo 2024-11-06  164  
7e6780184dc934 Vicentiu Galanopulo 2024-11-06  165  	mutex_lock(&chip->lock);
7e6780184dc934 Vicentiu Galanopulo 2024-11-06  166  
7e6780184dc934 Vicentiu Galanopulo 2024-11-06  167  	ret = st1202_read_reg(chip, ST1202_ILED_REG0 + led->led_num,
7e6780184dc934 Vicentiu Galanopulo 2024-11-06  168  				&value);
7e6780184dc934 Vicentiu Galanopulo 2024-11-06  169  	if (ret != 0)
7e6780184dc934 Vicentiu Galanopulo 2024-11-06  170  		dev_err(&chip->client->dev, "Reading register [0x%x] failed, error: %d\n",
7e6780184dc934 Vicentiu Galanopulo 2024-11-06  171  			ST1202_ILED_REG0 + led->led_num, ret);

Presumably value is uninitialized if st1202_read_reg() fails.  Normally
I would just mark st1202_read_reg() as a no-fail function and not
report it but here there is explicit error checking so it's weird.

7e6780184dc934 Vicentiu Galanopulo 2024-11-06  172  
7e6780184dc934 Vicentiu Galanopulo 2024-11-06  173  	mutex_unlock(&chip->lock);
7e6780184dc934 Vicentiu Galanopulo 2024-11-06  174  
7e6780184dc934 Vicentiu Galanopulo 2024-11-06 @175  	return value;
7e6780184dc934 Vicentiu Galanopulo 2024-11-06  176  }

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