[linux-next:master 6914/8209] drivers/watchdog/watchdog_core.c:283:65: warning: '%d' directive output may be truncated writing between 1 and 10 bytes into a region of size 8

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
head:   290aaf24a551d5a0dce037e3fab30820f9113a10
commit: e9f47fe866d6b0aa026fe99df94f8cc2fadc2638 [6914/8209] watchdog: take all OF aliases into account when assigning id
config: csky-allmodconfig (https://download.01.org/0day-ci/archive/20260722/[email protected]/config)
compiler: csky-linux-gcc (GCC) 16.1.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260722/[email protected]/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 <[email protected]>
| Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/

All warnings (new ones prefixed by >>):

   drivers/watchdog/watchdog_core.c: In function '___watchdog_register_device':
>> drivers/watchdog/watchdog_core.c:283:65: warning: '%d' directive output may be truncated writing between 1 and 10 bytes into a region of size 8 [-Wformat-truncation=]
     283 |                         snprintf(alias, sizeof(alias), "watchdog%d", id);
         |                                                                 ^~
   drivers/watchdog/watchdog_core.c:283:56: note: directive argument in the range [0, 2147483647]
     283 |                         snprintf(alias, sizeof(alias), "watchdog%d", id);
         |                                                        ^~~~~~~~~~~~
   drivers/watchdog/watchdog_core.c:283:25: note: 'snprintf' output between 10 and 19 bytes into a destination of size 16
     283 |                         snprintf(alias, sizeof(alias), "watchdog%d", id);
         |                         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


vim +283 drivers/watchdog/watchdog_core.c

   240	
   241	static int ___watchdog_register_device(struct watchdog_device *wdd)
   242	{
   243		int ret, min_id, id = -1;
   244		struct device_node *np;
   245		char alias[16];
   246	
   247		if (wdd == NULL || wdd->info == NULL || wdd->ops == NULL)
   248			return -EINVAL;
   249	
   250		/* Mandatory operations need to be supported */
   251		if (!wdd->ops->start || (!wdd->ops->stop && !wdd->max_hw_heartbeat_ms))
   252			return -EINVAL;
   253	
   254		watchdog_check_min_max_timeout(wdd);
   255	
   256		/*
   257		 * Note: now that all watchdog_device data has been verified, we
   258		 * will not check this anymore in other functions. If data gets
   259		 * corrupted in a later stage then we expect a kernel panic!
   260		 */
   261	
   262		/* Use alias for watchdog id if possible */
   263		if (wdd->parent) {
   264			ret = of_alias_get_id(wdd->parent->of_node, "watchdog");
   265			if (ret >= 0)
   266				id = ida_alloc_range(&watchdog_ida, ret, ret,
   267						     GFP_KERNEL);
   268		}
   269	
   270		/*
   271		 * Find an id which is not pre-assigned via a DT alias to some
   272		 * other, possibly not yet probed, watchdog device.
   273		 */
   274		if (id < 0) {
   275			np = of_find_node_by_path("/aliases");
   276	
   277			for (min_id = 0; ; min_id = id + 1) {
   278				id = ida_alloc_range(&watchdog_ida, min_id, MAX_DOGS - 1,
   279						     GFP_KERNEL);
   280				if (!np || id < 0)
   281					break;
   282	
 > 283				snprintf(alias, sizeof(alias), "watchdog%d", id);
   284				if (!of_get_property(np, alias, NULL))
   285					break;
   286				ida_free(&watchdog_ida, id);
   287			}
   288			of_node_put(np);
   289		}
   290	
   291		if (id < 0)
   292			return id;
   293		wdd->id = id;
   294	
   295		ret = watchdog_dev_register(wdd);
   296		if (ret) {
   297			ida_free(&watchdog_ida, id);
   298			if (!(id == 0 && ret == -EBUSY))
   299				return ret;
   300	
   301			/* Retry in case a legacy watchdog module exists */
   302			id = ida_alloc_range(&watchdog_ida, 1, MAX_DOGS - 1,
   303					     GFP_KERNEL);
   304			if (id < 0)
   305				return id;
   306			wdd->id = id;
   307	
   308			ret = watchdog_dev_register(wdd);
   309			if (ret) {
   310				ida_free(&watchdog_ida, id);
   311				return ret;
   312			}
   313		}
   314	
   315		/* Module parameter to force watchdog policy on reboot. */
   316		if (stop_on_reboot != -1) {
   317			if (stop_on_reboot)
   318				set_bit(WDOG_STOP_ON_REBOOT, &wdd->status);
   319			else
   320				clear_bit(WDOG_STOP_ON_REBOOT, &wdd->status);
   321		}
   322	
   323		if (test_bit(WDOG_STOP_ON_REBOOT, &wdd->status)) {
   324			if (!wdd->ops->stop)
   325				pr_warn("watchdog%d: stop_on_reboot not supported\n", wdd->id);
   326			else {
   327				wdd->reboot_nb.notifier_call = watchdog_reboot_notifier;
   328	
   329				ret = register_reboot_notifier(&wdd->reboot_nb);
   330				if (ret) {
   331					pr_err("watchdog%d: Cannot register reboot notifier (%d)\n",
   332						wdd->id, ret);
   333					watchdog_dev_unregister(wdd);
   334					ida_free(&watchdog_ida, id);
   335					return ret;
   336				}
   337			}
   338		}
   339	
   340		if (wdd->ops->restart) {
   341			wdd->restart_nb.notifier_call = watchdog_restart_notifier;
   342	
   343			ret = register_restart_handler(&wdd->restart_nb);
   344			if (ret)
   345				pr_warn("watchdog%d: Cannot register restart handler (%d)\n",
   346					wdd->id, ret);
   347		}
   348	
   349		if (test_bit(WDOG_NO_PING_ON_SUSPEND, &wdd->status)) {
   350			wdd->pm_nb.notifier_call = watchdog_pm_notifier;
   351	
   352			ret = register_pm_notifier(&wdd->pm_nb);
   353			if (ret)
   354				pr_warn("watchdog%d: Cannot register pm handler (%d)\n",
   355					wdd->id, ret);
   356		}
   357	
   358		return 0;
   359	}
   360	

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