drivers/gpu/drm/amd/amdgpu/amdgpu_securedisplay.c:141:37: warning: Undefined behavior: Variable 'i2c_output' is used as parameter and destination in

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

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   28806e4d9b97865b450d72156e9ad229f2067f0b
commit: ecaafb7b5ab6406587341d8727f237b3ee00dedf drm/amdgpu: Add secure display TA interface
date:   8 weeks ago
compiler: alpha-linux-gcc (GCC) 9.3.0

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


cppcheck possible warnings: (new ones prefixed by >>, may not real problems)

>> drivers/gpu/drm/amd/amdgpu/amdgpu_securedisplay.c:141:37: warning: Undefined behavior: Variable 'i2c_output' is used as parameter and destination in s[n]printf(). [sprintfOverlappingData]
        sprintf(i2c_output, "%s 0x%X", i2c_output,
                                       ^

vim +/i2c_output +141 drivers/gpu/drm/amd/amdgpu/amdgpu_securedisplay.c

    85	
    86	static ssize_t amdgpu_securedisplay_debugfs_write(struct file *f, const char __user *buf,
    87			size_t size, loff_t *pos)
    88	{
    89		struct amdgpu_device *adev = (struct amdgpu_device *)file_inode(f)->i_private;
    90		struct psp_context *psp = &adev->psp;
    91		struct securedisplay_cmd *securedisplay_cmd;
    92		struct drm_device *dev = adev_to_drm(adev);
    93		uint32_t phy_id;
    94		uint32_t op;
    95		int i;
    96		char str[64];
    97		char i2c_output[256];
    98		int ret;
    99	
   100		if (*pos || size > sizeof(str) - 1)
   101			return -EINVAL;
   102	
   103		memset(str,  0, sizeof(str));
   104		ret = copy_from_user(str, buf, size);
   105		if (ret)
   106			return -EFAULT;
   107	
   108		ret = pm_runtime_get_sync(dev->dev);
   109		if (ret < 0) {
   110			pm_runtime_put_autosuspend(dev->dev);
   111			return ret;
   112		}
   113	
   114		if (size < 3)
   115			sscanf(str, "%u ", &op);
   116		else
   117			sscanf(str, "%u %u", &op, &phy_id);
   118	
   119		switch (op) {
   120		case 1:
   121			psp_prep_securedisplay_cmd_buf(psp, &securedisplay_cmd,
   122				TA_SECUREDISPLAY_COMMAND__QUERY_TA);
   123			ret = psp_securedisplay_invoke(psp, TA_SECUREDISPLAY_COMMAND__QUERY_TA);
   124			if (!ret) {
   125				if (securedisplay_cmd->status == TA_SECUREDISPLAY_STATUS__SUCCESS)
   126					dev_info(adev->dev, "SECUREDISPLAY: query securedisplay TA ret is 0x%X\n",
   127						securedisplay_cmd->securedisplay_out_message.query_ta.query_cmd_ret);
   128				else
   129					psp_securedisplay_parse_resp_status(psp, securedisplay_cmd->status);
   130			}
   131			break;
   132		case 2:
   133			psp_prep_securedisplay_cmd_buf(psp, &securedisplay_cmd,
   134				TA_SECUREDISPLAY_COMMAND__SEND_ROI_CRC);
   135			securedisplay_cmd->securedisplay_in_message.send_roi_crc.phy_id = phy_id;
   136			ret = psp_securedisplay_invoke(psp, TA_SECUREDISPLAY_COMMAND__SEND_ROI_CRC);
   137			if (!ret) {
   138				if (securedisplay_cmd->status == TA_SECUREDISPLAY_STATUS__SUCCESS) {
   139					memset(i2c_output,  0, sizeof(i2c_output));
   140					for (i = 0; i < TA_SECUREDISPLAY_I2C_BUFFER_SIZE; i++)
 > 141						sprintf(i2c_output, "%s 0x%X", i2c_output,
   142							securedisplay_cmd->securedisplay_out_message.send_roi_crc.i2c_buf[i]);
   143					dev_info(adev->dev, "SECUREDISPLAY: I2C buffer out put is :%s\n", i2c_output);
   144				} else {
   145					psp_securedisplay_parse_resp_status(psp, securedisplay_cmd->status);
   146				}
   147			}
   148			break;
   149		default:
   150			dev_err(adev->dev, "Invalid input: %s\n", str);
   151		}
   152	
   153		pm_runtime_mark_last_busy(dev->dev);
   154		pm_runtime_put_autosuspend(dev->dev);
   155	
   156		return size;
   157	}
   158	

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