drivers/gpu/drm/imx/ipuv3/imx-ldb.c:658:57: warning: '_sel' directive output may be truncated writing 4 bytes into a region of size between 3 and 13

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

Hi Jani,

FYI, the error/warning still remains.

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   a8662bcd2ff152bfbc751cab20f33053d74d0963
commit: 03ee752f00fd0daa082b43774cfd03a7f9a17385 drm/imx: prefer snprintf over sprintf
date:   1 year, 2 months ago
config: csky-randconfig-r053-20231127 (https://download.01.org/0day-ci/archive/20250405/202504052118.HCpNF13P-lkp@intel.com/config)
compiler: csky-linux-gcc (GCC) 12.4.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250405/202504052118.HCpNF13P-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/202504052118.HCpNF13P-lkp@intel.com/

All warnings (new ones prefixed by >>):

   drivers/gpu/drm/imx/ipuv3/imx-ldb.c: In function 'imx_ldb_probe':
>> drivers/gpu/drm/imx/ipuv3/imx-ldb.c:658:57: warning: '_sel' directive output may be truncated writing 4 bytes into a region of size between 3 and 13 [-Wformat-truncation=]
     658 |                 snprintf(clkname, sizeof(clkname), "di%d_sel", i);
         |                                                         ^~~~
   drivers/gpu/drm/imx/ipuv3/imx-ldb.c:658:17: note: 'snprintf' output between 8 and 18 bytes into a destination of size 16
     658 |                 snprintf(clkname, sizeof(clkname), "di%d_sel", i);
         |                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


vim +/_sel +658 drivers/gpu/drm/imx/ipuv3/imx-ldb.c

   617	
   618	static int imx_ldb_probe(struct platform_device *pdev)
   619	{
   620		struct device *dev = &pdev->dev;
   621		struct device_node *np = dev->of_node;
   622		struct device_node *child;
   623		struct imx_ldb *imx_ldb;
   624		int dual;
   625		int ret;
   626		int i;
   627	
   628		imx_ldb = devm_kzalloc(dev, sizeof(*imx_ldb), GFP_KERNEL);
   629		if (!imx_ldb)
   630			return -ENOMEM;
   631	
   632		imx_ldb->regmap = syscon_regmap_lookup_by_phandle(np, "gpr");
   633		if (IS_ERR(imx_ldb->regmap)) {
   634			dev_err(dev, "failed to get parent regmap\n");
   635			return PTR_ERR(imx_ldb->regmap);
   636		}
   637	
   638		/* disable LDB by resetting the control register to POR default */
   639		regmap_write(imx_ldb->regmap, IOMUXC_GPR2, 0);
   640	
   641		imx_ldb->dev = dev;
   642		imx_ldb->lvds_mux = device_get_match_data(dev);
   643	
   644		dual = of_property_read_bool(np, "fsl,dual-channel");
   645		if (dual)
   646			imx_ldb->ldb_ctrl |= LDB_SPLIT_MODE_EN;
   647	
   648		/*
   649		 * There are three different possible clock mux configurations:
   650		 * i.MX53:  ipu1_di0_sel, ipu1_di1_sel
   651		 * i.MX6q:  ipu1_di0_sel, ipu1_di1_sel, ipu2_di0_sel, ipu2_di1_sel
   652		 * i.MX6dl: ipu1_di0_sel, ipu1_di1_sel, lcdif_sel
   653		 * Map them all to di0_sel...di3_sel.
   654		 */
   655		for (i = 0; i < 4; i++) {
   656			char clkname[16];
   657	
 > 658			snprintf(clkname, sizeof(clkname), "di%d_sel", i);
   659			imx_ldb->clk_sel[i] = devm_clk_get(imx_ldb->dev, clkname);
   660			if (IS_ERR(imx_ldb->clk_sel[i])) {
   661				ret = PTR_ERR(imx_ldb->clk_sel[i]);
   662				imx_ldb->clk_sel[i] = NULL;
   663				break;
   664			}
   665	
   666			imx_ldb->clk_parent[i] = clk_get_parent(imx_ldb->clk_sel[i]);
   667		}
   668		if (i == 0)
   669			return ret;
   670	
   671		for_each_child_of_node(np, child) {
   672			struct imx_ldb_channel *channel;
   673			int bus_format;
   674	
   675			ret = of_property_read_u32(child, "reg", &i);
   676			if (ret || i < 0 || i > 1) {
   677				ret = -EINVAL;
   678				goto free_child;
   679			}
   680	
   681			if (!of_device_is_available(child))
   682				continue;
   683	
   684			if (dual && i > 0) {
   685				dev_warn(dev, "dual-channel mode, ignoring second output\n");
   686				continue;
   687			}
   688	
   689			channel = &imx_ldb->channel[i];
   690			channel->ldb = imx_ldb;
   691			channel->chno = i;
   692	
   693			/*
   694			 * The output port is port@4 with an external 4-port mux or
   695			 * port@2 with the internal 2-port mux.
   696			 */
   697			ret = drm_of_find_panel_or_bridge(child,
   698							  imx_ldb->lvds_mux ? 4 : 2, 0,
   699							  &channel->panel, &channel->bridge);
   700			if (ret && ret != -ENODEV)
   701				goto free_child;
   702	
   703			/* panel ddc only if there is no bridge */
   704			if (!channel->bridge) {
   705				ret = imx_ldb_panel_ddc(dev, channel, child);
   706				if (ret)
   707					goto free_child;
   708			}
   709	
   710			bus_format = of_get_bus_format(dev, child);
   711			if (bus_format == -EINVAL) {
   712				/*
   713				 * If no bus format was specified in the device tree,
   714				 * we can still get it from the connected panel later.
   715				 */
   716				if (channel->panel && channel->panel->funcs &&
   717				    channel->panel->funcs->get_modes)
   718					bus_format = 0;
   719			}
   720			if (bus_format < 0) {
   721				dev_err(dev, "could not determine data mapping: %d\n",
   722					bus_format);
   723				ret = bus_format;
   724				goto free_child;
   725			}
   726			channel->bus_format = bus_format;
   727			channel->child = child;
   728		}
   729	
   730		platform_set_drvdata(pdev, imx_ldb);
   731	
   732		return component_add(&pdev->dev, &imx_ldb_ops);
   733	
   734	free_child:
   735		of_node_put(child);
   736		return ret;
   737	}
   738	

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https://github.com/intel/lkp-tests/wiki