[jimc:dd-ratelimit 57/81] lib/dynamic_debug.c:1987:3: warning: variable 'i' is uninitialized when used here

tree:   https://github.com/jimc/linux.git dd-ratelimit
head:   cbb49cd4279ef7137b7931337dbbc47d7f9532d0
commit: 75e0f7b4820647e0712c667269fc5c720aa378c5 [57/81] dyndbg: walk dd_mod_map intervals in dynamic_debug_init()
config: hexagon-randconfig-002-20260729 (https://download.01.org/0day-ci/archive/20260730/[email protected]/config)
compiler: clang version 17.0.6 (https://github.com/llvm/llvm-project 6009708b4367171ccdbf4b5905cb6a803753fe18)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260730/[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 >>):

>> lib/dynamic_debug.c:1987:3: warning: variable 'i' is uninitialized when used here [-Wuninitialized]
    1987 |                 i += mod_di.descs.len;
         |                 ^
   lib/dynamic_debug.c:1910:7: note: initialize the variable 'i' to silence this warning
    1910 |         int i, ret = 0, mod_ct = 0;
         |              ^
         |               = 0
   1 warning generated.


vim +/i +1987 lib/dynamic_debug.c

  1934	
  1935		if (&__start___dyndbg_descs == &__stop___dyndbg_descs) {
  1936			if (IS_ENABLED(CONFIG_DYNAMIC_DEBUG)) {
  1937				pr_warn("_ddebug table is empty in a CONFIG_DYNAMIC_DEBUG build\n");
  1938				return 1;
  1939			}
  1940			pr_info("Ignore empty _ddebug table in a CONFIG_DYNAMIC_DEBUG_CORE build\n");
  1941			ddebug_init_success = 1;
  1942			return 0;
  1943		}
  1944		/*
  1945		 * fill the 3 function, file, module trees with the values and
  1946		 * their intervals, and then walk the module intervals and
  1947		 * call add_module for each.
  1948		 */
  1949		ddebug_condense_sites(&di);
  1950	
  1951		/*
  1952		 * under rcu-lock, gather the modules' descriptor intervals
  1953		 * into an atomically alloc'd list
  1954		 */
  1955		rcu_read_lock();
  1956		MA_STATE(mas, &dd_mod_map, 0, ULONG_MAX);
  1957		mas_for_each(&mas, mod_name, ULONG_MAX) {
  1958			mod_info = kmalloc(sizeof(*mod_info), GFP_ATOMIC);
  1959			if (!mod_info) {
  1960				pr_warn("kmalloc failed, some modules may not be processed\n");
  1961				break;
  1962			}
  1963			mod_info->mod_name = (const char *)mod_name;
  1964			mod_info->start_addr = mas.index;
  1965			mod_info->end_addr = mas.last;
  1966			list_add_tail(&mod_info->link, &mod_list);
  1967		}
  1968		rcu_read_unlock();
  1969	
  1970		/*
  1971		 * walk the list, call ddebug_add_module for each, which may sleep
  1972		 */
  1973		list_for_each_entry_safe(mod_info, tmp, &mod_list, link) {
  1974			struct _ddebug_info mod_di = di;
  1975	
  1976			mod_di.mod_name = mod_info->mod_name;
  1977			mod_di.descs.start = (struct _ddebug *)mod_info->start_addr;
  1978			mod_di.descs.len = (mod_info->end_addr - mod_info->start_addr) / sizeof(struct _ddebug) + 1;
  1979	
  1980			ret = ddebug_add_module(&mod_di);
  1981			if (ret) {
  1982				pr_err("Failed to add module %s, error %d\n",
  1983				       mod_di.mod_name, ret);
  1984				goto out_err;
  1985			}
  1986			mod_ct++;
> 1987			i += mod_di.descs.len;
  1988			list_del(&mod_info->link);
  1989			kfree(mod_info);
  1990		}
  1991	
  1992		ddebug_init_success = 1;
  1993		vpr_info("%d prdebugs in %d modules, %d KiB in ddebug tables, %d+%d kiB in __dyndbg:_descs+_sites sections\n",
  1994			 i, mod_ct, (int)((mod_ct * sizeof(struct ddebug_table)) >> 10),
  1995			 (int)((i * sizeof(struct _ddebug)) >> 10),
  1996			 (int)((i * sizeof(struct _ddebug_site)) >> 10));
  1997	
  1998		if (di.maps.len)
  1999			v2pr_info("  %d builtin ddebug class-maps\n", di.maps.len);
  2000	
  2001		/* now that ddebug tables are loaded, process all boot args
  2002		 * again to find and activate queries given in dyndbg params.
  2003		 * While this has already been done for known boot params, it
  2004		 * ignored the unknown ones (dyndbg in particular).  Reusing
  2005		 * parse_args avoids ad-hoc parsing.  This will also attempt
  2006		 * to activate queries for not-yet-loaded modules, which is
  2007		 * slightly noisy if verbose, but harmless.
  2008		 */
  2009		cmdline = kstrdup(saved_command_line, GFP_KERNEL);
  2010		parse_args("dyndbg params", cmdline, NULL,
  2011			   0, 0, 0, NULL, &ddebug_dyndbg_boot_param_cb);
  2012		kfree(cmdline);
  2013		return 0;
  2014	
  2015	out_err:
  2016		/* Clean up any remaining items in mod_list on error */
  2017		list_for_each_entry_safe(mod_info, tmp, &mod_list, link) {
  2018			list_del(&mod_info->link);
  2019			kfree(mod_info);
  2020		}
  2021		ddebug_remove_all_tables();
  2022		return ret;
  2023	}
  2024	/* Allow early initialization for boot messages via boot param */
  2025	early_initcall(dynamic_debug_init);
  2026	

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