[akpm-mm:mm-unstable 61/88] mm/cma_debug.c:189:55: warning: '%d' directive output may be truncated writing between 1 and 11 bytes into a region of size 3

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

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-unstable
head:   495206a68b359eb6117d0860861578113bbb94e7
commit: 77cbd63e91fa6c5f6157a30e61a380b6c47c1443 [61/88] mm, cma: support multiple contiguous ranges, if requested
config: x86_64-buildonly-randconfig-003-20250131 (https://download.01.org/0day-ci/archive/20250131/202501311125.wbG1DN2B-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250131/202501311125.wbG1DN2B-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/202501311125.wbG1DN2B-lkp@intel.com/

All warnings (new ones prefixed by >>):

   mm/cma_debug.c: In function 'cma_debugfs_add_one':
>> mm/cma_debug.c:189:55: warning: '%d' directive output may be truncated writing between 1 and 11 bytes into a region of size 3 [-Wformat-truncation=]
     189 |                 snprintf(rdirname, sizeof(rdirname), "%d", r);
         |                                                       ^~
   mm/cma_debug.c:189:54: note: directive argument in the range [-2147483644, 2147483646]
     189 |                 snprintf(rdirname, sizeof(rdirname), "%d", r);
         |                                                      ^~~~
   mm/cma_debug.c:189:17: note: 'snprintf' output between 2 and 12 bytes into a destination of size 3
     189 |                 snprintf(rdirname, sizeof(rdirname), "%d", r);
         |                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


vim +189 mm/cma_debug.c

   168	
   169	static void cma_debugfs_add_one(struct cma *cma, struct dentry *root_dentry)
   170	{
   171		struct dentry *tmp, *dir, *rangedir;
   172		int r;
   173		char rdirname[3];
   174		struct cma_memrange *cmr;
   175	
   176		tmp = debugfs_create_dir(cma->name, root_dentry);
   177	
   178		debugfs_create_file("alloc", 0200, tmp, cma, &cma_alloc_fops);
   179		debugfs_create_file("free", 0200, tmp, cma, &cma_free_fops);
   180		debugfs_create_file("count", 0444, tmp, &cma->count, &cma_debugfs_fops);
   181		debugfs_create_file("order_per_bit", 0444, tmp,
   182				    &cma->order_per_bit, &cma_debugfs_fops);
   183		debugfs_create_file("used", 0444, tmp, cma, &cma_used_fops);
   184		debugfs_create_file("maxchunk", 0444, tmp, cma, &cma_maxchunk_fops);
   185	
   186		rangedir = debugfs_create_dir("ranges", tmp);
   187		for (r = 0; r < cma->nranges; r++) {
   188			cmr = &cma->ranges[r];
 > 189			snprintf(rdirname, sizeof(rdirname), "%d", r);
   190			dir = debugfs_create_dir(rdirname, rangedir);
   191			debugfs_create_file("base_pfn", 0444, dir,
   192				    &cmr->base_pfn, &cma_debugfs_fops);
   193			cmr->dfs_bitmap.array = (u32 *)cmr->bitmap;
   194			cmr->dfs_bitmap.n_elements =
   195				DIV_ROUND_UP(cma_bitmap_maxno(cma, cmr),
   196						BITS_PER_BYTE * sizeof(u32));
   197			debugfs_create_u32_array("bitmap", 0444, dir,
   198					&cmr->dfs_bitmap);
   199		}
   200	
   201		/*
   202		 * Backward compatible symlinks to range 0 for base_pfn and bitmap.
   203		 */
   204		debugfs_create_symlink("base_pfn", tmp, "ranges/0/base_pfn");
   205		debugfs_create_symlink("bitmap", tmp, "ranges/0/bitmap");
   206	}
   207	

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