Re: [PATCH 2/2] nvmem: core: Expose cells through sysfs

[Miquel Raynal <miquel.raynal@bootlin.com>]

Hi Dan,

dan.carpenter@linaro.org wrote on Mon, 29 May 2023 07:28:59 +0300:

> Hi Miquel,
> 
> 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/Miquel-Raynal/ABI-sysfs-nvmem-cells-Expose-cells-through-sysfs/20230523-203042
> base:   char-misc/char-misc-testing
> patch link:    https://lore.kernel.org/r/20230523100239.307574-3-miquel.raynal%40bootlin.com
> patch subject: [PATCH 2/2] nvmem: core: Expose cells through sysfs
> config: i386-randconfig-m021-20230525 (https://download.01.org/0day-ci/archive/20230528/202305280054.NloN5RLk-lkp@intel.com/config)
> compiler: gcc-11 (Debian 11.3.0-12) 11.3.0
> 
> If you fix the issue, kindly add following tag where applicable
> | Reported-by: kernel test robot <lkp@intel.com>
> | Reported-by: Dan Carpenter <error27@gmail.com>
> | Closes: https://lore.kernel.org/r/202305280054.NloN5RLk-lkp@intel.com/
> 
> smatch warnings:
> drivers/nvmem/core.c:380 nvmem_cell_attr_read() error: uninitialized symbol 'read_len'.
> 
> vim +/read_len +380 drivers/nvmem/core.c
> 
> 22c370b2163e59 Miquel Raynal       2023-05-23  328  static struct nvmem_cell *nvmem_create_cell(struct nvmem_cell_entry *entry,
> 22c370b2163e59 Miquel Raynal       2023-05-23  329  					    const char *id, int index);
> 22c370b2163e59 Miquel Raynal       2023-05-23  330  
> 22c370b2163e59 Miquel Raynal       2023-05-23  331  static ssize_t nvmem_cell_attr_read(struct file *filp, struct kobject *kobj,
> 22c370b2163e59 Miquel Raynal       2023-05-23  332  				    struct bin_attribute *attr, char *buf,
> 22c370b2163e59 Miquel Raynal       2023-05-23  333  				    loff_t pos, size_t count)
> 22c370b2163e59 Miquel Raynal       2023-05-23  334  {
> 22c370b2163e59 Miquel Raynal       2023-05-23  335  	struct nvmem_cell_entry *entry;
> 22c370b2163e59 Miquel Raynal       2023-05-23  336  	struct nvmem_cell *cell = NULL;
> 22c370b2163e59 Miquel Raynal       2023-05-23  337  	struct nvmem_device *nvmem;
> 22c370b2163e59 Miquel Raynal       2023-05-23  338  	size_t cell_sz, read_len;
> 22c370b2163e59 Miquel Raynal       2023-05-23  339  	struct device *dev;
> 22c370b2163e59 Miquel Raynal       2023-05-23  340  	void *content;
> 22c370b2163e59 Miquel Raynal       2023-05-23  341  
> 22c370b2163e59 Miquel Raynal       2023-05-23  342  	if (attr->private)
> 22c370b2163e59 Miquel Raynal       2023-05-23  343  		dev = attr->private;
> 22c370b2163e59 Miquel Raynal       2023-05-23  344  	else
> 22c370b2163e59 Miquel Raynal       2023-05-23  345  		dev = kobj_to_dev(kobj);
> 22c370b2163e59 Miquel Raynal       2023-05-23  346  	nvmem = to_nvmem_device(dev);
> 22c370b2163e59 Miquel Raynal       2023-05-23  347  
> 22c370b2163e59 Miquel Raynal       2023-05-23  348  	mutex_lock(&nvmem_mutex);
> 22c370b2163e59 Miquel Raynal       2023-05-23  349  	list_for_each_entry(entry, &nvmem->cells, node) {
> 22c370b2163e59 Miquel Raynal       2023-05-23  350  		if (strncmp(entry->name, attr->attr.name, XATTR_NAME_MAX))
> 22c370b2163e59 Miquel Raynal       2023-05-23  351  			continue;
> 22c370b2163e59 Miquel Raynal       2023-05-23  352  
> 22c370b2163e59 Miquel Raynal       2023-05-23  353  		cell = nvmem_create_cell(entry, entry->name, 0);
> 22c370b2163e59 Miquel Raynal       2023-05-23  354  		if (IS_ERR(cell)) {
> 22c370b2163e59 Miquel Raynal       2023-05-23  355  			mutex_unlock(&nvmem_mutex);
> 22c370b2163e59 Miquel Raynal       2023-05-23  356  			return PTR_ERR(cell);
> 22c370b2163e59 Miquel Raynal       2023-05-23  357  		}
> 22c370b2163e59 Miquel Raynal       2023-05-23  358  
> 22c370b2163e59 Miquel Raynal       2023-05-23  359  		break;
> 22c370b2163e59 Miquel Raynal       2023-05-23  360  	}
> 22c370b2163e59 Miquel Raynal       2023-05-23  361  	mutex_unlock(&nvmem_mutex);
> 22c370b2163e59 Miquel Raynal       2023-05-23  362  
> 22c370b2163e59 Miquel Raynal       2023-05-23  363  	if (!cell)
> 22c370b2163e59 Miquel Raynal       2023-05-23  364  		return -EINVAL;
> 22c370b2163e59 Miquel Raynal       2023-05-23  365  
> 22c370b2163e59 Miquel Raynal       2023-05-23  366  	content = nvmem_cell_read(cell, &cell_sz);
> 22c370b2163e59 Miquel Raynal       2023-05-23  367  	if (IS_ERR(content)) {
> 22c370b2163e59 Miquel Raynal       2023-05-23  368  		count = PTR_ERR(content);
> 22c370b2163e59 Miquel Raynal       2023-05-23  369  		goto destroy_cell;
> 
> read_len not initialized on this goto path.

It should be:							read_len = PTR_ERR...

I will correct this in the next version, thanks for the report.

> 
> 22c370b2163e59 Miquel Raynal       2023-05-23  370  	}
> 22c370b2163e59 Miquel Raynal       2023-05-23  371  
> 22c370b2163e59 Miquel Raynal       2023-05-23  372  	read_len = min_t(unsigned int, cell_sz - pos, count);
> 22c370b2163e59 Miquel Raynal       2023-05-23  373  	memcpy(buf, content + pos, read_len);
> 22c370b2163e59 Miquel Raynal       2023-05-23  374  	kfree(content);
> 22c370b2163e59 Miquel Raynal       2023-05-23  375  
> 22c370b2163e59 Miquel Raynal       2023-05-23  376  destroy_cell:
> 22c370b2163e59 Miquel Raynal       2023-05-23  377  	kfree_const(cell->id);
> 22c370b2163e59 Miquel Raynal       2023-05-23  378  	kfree(cell);
> 22c370b2163e59 Miquel Raynal       2023-05-23  379  
> 22c370b2163e59 Miquel Raynal       2023-05-23 @380  	return read_len;
>                                                         ^^^^^^^^^^^^^^^
> 
> 22c370b2163e59 Miquel Raynal       2023-05-23  381  }
> 


Thanks,
Miquèl