drivers/memory/tegra/tegra186.c:74:49: warning: '%u' directive output may be truncated writing between 1 and 10 bytes into a region of size 6

drivers/memory/tegra/tegra186.c:74:49: warning: '%u' directive output may be truncated writing between 1 and 10 bytes into a region of size 6

[kernel test robot]

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   06dc10eae55b5ceabfef287a7e5f16ceea204aa0
commit: a7cffa11fa9232eabf0c4f441dc53002978ab526 memory: tegra: Add memory controller channels support
date:   1 year, 5 months ago
config: arm64-randconfig-r036-20230512 (https://download.01.org/0day-ci/archive/20231018/202310182004.0XOYolzI-lkp@intel.com/config)
compiler: aarch64-linux-gcc (GCC) 11.3.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231018/202310182004.0XOYolzI-lkp@intel.com/reproduce)

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>
| Closes: https://lore.kernel.org/oe-kbuild-all/202310182004.0XOYolzI-lkp@intel.com/

All warnings (new ones prefixed by >>):

   drivers/memory/tegra/tegra186.c: In function 'tegra186_mc_probe':
>> drivers/memory/tegra/tegra186.c:74:49: warning: '%u' directive output may be truncated writing between 1 and 10 bytes into a region of size 6 [-Wformat-truncation=]
      74 |                 snprintf(name, sizeof(name), "ch%u", i);
         |                                                 ^~
   drivers/memory/tegra/tegra186.c:74:46: note: directive argument in the range [0, 4294967294]
      74 |                 snprintf(name, sizeof(name), "ch%u", i);
         |                                              ^~~~~~
   drivers/memory/tegra/tegra186.c:74:17: note: 'snprintf' output between 4 and 13 bytes into a destination of size 8
      74 |                 snprintf(name, sizeof(name), "ch%u", i);
         |                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


vim +74 drivers/memory/tegra/tegra186.c

    48	
    49	static int tegra186_mc_probe(struct tegra_mc *mc)
    50	{
    51		struct platform_device *pdev = to_platform_device(mc->dev);
    52		unsigned int i;
    53		char name[8];
    54		int err;
    55	
    56		mc->bcast_ch_regs = devm_platform_ioremap_resource_byname(pdev, "broadcast");
    57		if (IS_ERR(mc->bcast_ch_regs)) {
    58			if (PTR_ERR(mc->bcast_ch_regs) == -EINVAL) {
    59				dev_warn(&pdev->dev,
    60					 "Broadcast channel is missing, please update your device-tree\n");
    61				mc->bcast_ch_regs = NULL;
    62				goto populate;
    63			}
    64	
    65			return PTR_ERR(mc->bcast_ch_regs);
    66		}
    67	
    68		mc->ch_regs = devm_kcalloc(mc->dev, mc->soc->num_channels, sizeof(*mc->ch_regs),
    69					   GFP_KERNEL);
    70		if (!mc->ch_regs)
    71			return -ENOMEM;
    72	
    73		for (i = 0; i < mc->soc->num_channels; i++) {
  > 74			snprintf(name, sizeof(name), "ch%u", i);
    75	
    76			mc->ch_regs[i] = devm_platform_ioremap_resource_byname(pdev, name);
    77			if (IS_ERR(mc->ch_regs[i]))
    78				return PTR_ERR(mc->ch_regs[i]);
    79		}
    80	
    81	populate:
    82		err = of_platform_populate(mc->dev->of_node, NULL, NULL, mc->dev);
    83		if (err < 0)
    84			return err;
    85	
    86		tegra186_mc_program_sid(mc);
    87	
    88		return 0;
    89	}
    90	

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

Re: drivers/memory/tegra/tegra186.c:74:49: warning: '%u' directive output may be truncated writing between 1 and 10 bytes into a region of size 6

[Krzysztof Kozlowski]

On 18/10/2023 14:32, kernel test robot wrote:
> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> head:   06dc10eae55b5ceabfef287a7e5f16ceea204aa0
> commit: a7cffa11fa9232eabf0c4f441dc53002978ab526 memory: tegra: Add memory controller channels support
> date:   1 year, 5 months ago
> config: arm64-randconfig-r036-20230512 (https://download.01.org/0day-ci/archive/20231018/202310182004.0XOYolzI-lkp@intel.com/config)
> compiler: aarch64-linux-gcc (GCC) 11.3.0
> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231018/202310182004.0XOYolzI-lkp@intel.com/reproduce)
> 
> 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>
> | Closes: https://lore.kernel.org/oe-kbuild-all/202310182004.0XOYolzI-lkp@intel.com/
> 
> All warnings (new ones prefixed by >>):

Ashish,

Are you planning to respond to this?

Best regards,
Krzysztof

Re: drivers/memory/tegra/tegra186.c:74:49: warning: '%u' directive output may be truncated writing between 1 and 10 bytes into a region of size 6

[Ashish Mhetre]

On 10/19/2023 7:06 PM, Krzysztof Kozlowski wrote:
> External email: Use caution opening links or attachments
>
>
> On 18/10/2023 14:32, kernel test robot wrote:
>> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
>> head:   06dc10eae55b5ceabfef287a7e5f16ceea204aa0
>> commit: a7cffa11fa9232eabf0c4f441dc53002978ab526 memory: tegra: Add memory controller channels support
>> date:   1 year, 5 months ago
>> config: arm64-randconfig-r036-20230512 (https://download.01.org/0day-ci/archive/20231018/202310182004.0XOYolzI-lkp@intel.com/config)
>> compiler: aarch64-linux-gcc (GCC) 11.3.0
>> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231018/202310182004.0XOYolzI-lkp@intel.com/reproduce)
>>
>> 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>
>> | Closes: https://lore.kernel.org/oe-kbuild-all/202310182004.0XOYolzI-lkp@intel.com/
>>
>> All warnings (new ones prefixed by >>):
> Ashish,
>
> Are you planning to respond to this?
>
> Best regards,
> Krzysztof

Hi Krzysztof,

The value of mc->soc->num_channels is not more that 16. The number of
characters written in 'name' variable won't be more than 4 which is less
than buffer size of 8 bytes. So, can we ignore this warning?
If not, then I can fix this with a patch to check the return value of
snprintf and compare that with size of buffer 'name'. Something like:

-               snprintf(name, sizeof(name), "ch%u", i);
+               int n = snprintf(name, sizeof(name), "ch%u", i);
+
+               if (n < 0) {
+                       dev_err(&pdev->dev, "snprintf failed\n");
+                       return -EFAULT;
+               }
+               if ((size_t)n > sizeof(name)) {
+                       dev_err(&pdev->dev, "snprintf output is 
truncated\n");
+                       return -EFAULT;
+               }

Thanks,

Ashish Mhetre