Re: [PATCH v2 2/2] hwmon: Add "label" attribute

[kernel test robot <lkp@intel.com>]

Hi Paul,

I love your patch! Perhaps something to improve:

[auto build test WARNING on groeck-staging/hwmon-next]
[also build test WARNING on v5.16-rc8 next-20220105]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Paul-Cercueil/hwmon-Add-label-attribute-v2/20220105-231930
base:   https://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging.git hwmon-next
config: arm64-randconfig-r026-20220105 (https://download.01.org/0day-ci/archive/20220106/202201060630.vsp02mfB-lkp@intel.com/config)
compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project d5b6e30ed3acad794dd0aec400e617daffc6cc3d)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # install arm64 cross compiling tool for clang build
        # apt-get install binutils-aarch64-linux-gnu
        # https://github.com/0day-ci/linux/commit/57dab49995d01d638d9fa9aaddb5fa48e17b3c48
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Paul-Cercueil/hwmon-Add-label-attribute-v2/20220105-231930
        git checkout 57dab49995d01d638d9fa9aaddb5fa48e17b3c48
        # save the config file to linux build tree
        mkdir build_dir
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=arm64 SHELL=/bin/bash drivers/hwmon/

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

>> drivers/hwmon/hwmon.c:777:7: warning: variable 'hdev' is used uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized]
                   if (hwdev->label == NULL) {
                       ^~~~~~~~~~~~~~~~~~~~
   drivers/hwmon/hwmon.c:851:20: note: uninitialized use occurs here
           hwmon_dev_release(hdev);
                             ^~~~
   drivers/hwmon/hwmon.c:777:3: note: remove the 'if' if its condition is always false
                   if (hwdev->label == NULL) {
                   ^~~~~~~~~~~~~~~~~~~~~~~~~~~
   drivers/hwmon/hwmon.c:773:7: warning: variable 'hdev' is used uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized]
                   if (err < 0)
                       ^~~~~~~
   drivers/hwmon/hwmon.c:851:20: note: uninitialized use occurs here
           hwmon_dev_release(hdev);
                             ^~~~
   drivers/hwmon/hwmon.c:773:3: note: remove the 'if' if its condition is always false
                   if (err < 0)
                   ^~~~~~~~~~~~
   drivers/hwmon/hwmon.c:752:21: note: initialize the variable 'hdev' to silence this warning
           struct device *hdev;
                              ^
                               = NULL
   2 warnings generated.


vim +777 drivers/hwmon/hwmon.c

   744	
   745	static struct device *
   746	__hwmon_device_register(struct device *dev, const char *name, void *drvdata,
   747				const struct hwmon_chip_info *chip,
   748				const struct attribute_group **groups)
   749	{
   750		struct hwmon_device *hwdev;
   751		const char *label;
   752		struct device *hdev;
   753		int i, err, id;
   754	
   755		/* Complain about invalid characters in hwmon name attribute */
   756		if (name && (!strlen(name) || strpbrk(name, "-* \t\n")))
   757			dev_warn(dev,
   758				 "hwmon: '%s' is not a valid name attribute, please fix\n",
   759				 name);
   760	
   761		id = ida_simple_get(&hwmon_ida, 0, 0, GFP_KERNEL);
   762		if (id < 0)
   763			return ERR_PTR(id);
   764	
   765		hwdev = kzalloc(sizeof(*hwdev), GFP_KERNEL);
   766		if (hwdev == NULL) {
   767			err = -ENOMEM;
   768			goto ida_remove;
   769		}
   770	
   771		if (device_property_present(dev, "label")) {
   772			err = device_property_read_string(dev, "label", &label);
   773			if (err < 0)
   774				goto free_hwmon;
   775	
   776			hwdev->label = kstrdup(label, GFP_KERNEL);
 > 777			if (hwdev->label == NULL) {
   778				err = -ENOMEM;
   779				goto free_hwmon;
   780			}
   781		}
   782	
   783		hdev = &hwdev->dev;
   784	
   785		if (chip) {
   786			struct attribute **attrs;
   787			int ngroups = 2; /* terminating NULL plus &hwdev->groups */
   788	
   789			if (groups)
   790				for (i = 0; groups[i]; i++)
   791					ngroups++;
   792	
   793			hwdev->groups = kcalloc(ngroups, sizeof(*groups), GFP_KERNEL);
   794			if (!hwdev->groups) {
   795				err = -ENOMEM;
   796				goto free_hwmon;
   797			}
   798	
   799			attrs = __hwmon_create_attrs(drvdata, chip);
   800			if (IS_ERR(attrs)) {
   801				err = PTR_ERR(attrs);
   802				goto free_hwmon;
   803			}
   804	
   805			hwdev->group.attrs = attrs;
   806			ngroups = 0;
   807			hwdev->groups[ngroups++] = &hwdev->group;
   808	
   809			if (groups) {
   810				for (i = 0; groups[i]; i++)
   811					hwdev->groups[ngroups++] = groups[i];
   812			}
   813	
   814			hdev->groups = hwdev->groups;
   815		} else {
   816			hdev->groups = groups;
   817		}
   818	
   819		hwdev->name = name;
   820		hdev->class = &hwmon_class;
   821		hdev->parent = dev;
   822		hdev->of_node = dev ? dev->of_node : NULL;
   823		hwdev->chip = chip;
   824		dev_set_drvdata(hdev, drvdata);
   825		dev_set_name(hdev, HWMON_ID_FORMAT, id);
   826		err = device_register(hdev);
   827		if (err) {
   828			put_device(hdev);
   829			goto ida_remove;
   830		}
   831	
   832		INIT_LIST_HEAD(&hwdev->tzdata);
   833	
   834		if (dev && dev->of_node && chip && chip->ops->read &&
   835		    chip->info[0]->type == hwmon_chip &&
   836		    (chip->info[0]->config[0] & HWMON_C_REGISTER_TZ)) {
   837			err = hwmon_thermal_register_sensors(hdev);
   838			if (err) {
   839				device_unregister(hdev);
   840				/*
   841				 * Don't worry about hwdev; hwmon_dev_release(), called
   842				 * from device_unregister(), will free it.
   843				 */
   844				goto ida_remove;
   845			}
   846		}
   847	
   848		return hdev;
   849	
   850	free_hwmon:
   851		hwmon_dev_release(hdev);
   852	ida_remove:
   853		ida_simple_remove(&hwmon_ida, id);
   854		return ERR_PTR(err);
   855	}
   856	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org