[cifs:for-next 8/8] fs/cifs/dfs_cache.c:1294:2: warning: variable 'ppath' is used uninitialized whenever 'if' condition is false

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

tree:   git://git.samba.org/sfrench/cifs-2.6.git for-next
head:   ef605e86821253d16d47a02ce1f766a461614fef
commit: ef605e86821253d16d47a02ce1f766a461614fef [8/8] cifs: skip trailing separators of prefix paths
config: arm-randconfig-c002-20220603 (https://download.01.org/0day-ci/archive/20220604/202206041223.Kx81JSQt-lkp@intel.com/config)
compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project b364c76683f8ef241025a9556300778c07b590c2)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # install arm cross compiling tool for clang build
        # apt-get install binutils-arm-linux-gnueabi
        git remote add cifs git://git.samba.org/sfrench/cifs-2.6.git
        git fetch --no-tags cifs for-next
        git checkout ef605e86821253d16d47a02ce1f766a461614fef
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=arm SHELL=/bin/bash fs/cifs/

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

All warnings (new ones prefixed by >>):

>> fs/cifs/dfs_cache.c:1294:2: warning: variable 'ppath' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized]
           if (target_pplen || dfsref_pplen) {
           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/compiler.h:56:28: note: expanded from macro 'if'
   #define if(cond, ...) if ( __trace_if_var( !!(cond , ## __VA_ARGS__) ) )
                              ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/compiler.h:58:30: note: expanded from macro '__trace_if_var'
   #define __trace_if_var(cond) (__builtin_constant_p(cond) ? (cond) : __trace_if_value(cond))
                                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   fs/cifs/dfs_cache.c:1307:12: note: uninitialized use occurs here
           *prefix = ppath;
                     ^~~~~
   fs/cifs/dfs_cache.c:1294:2: note: remove the 'if' if its condition is always true
           if (target_pplen || dfsref_pplen) {
           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/compiler.h:56:23: note: expanded from macro 'if'
   #define if(cond, ...) if ( __trace_if_var( !!(cond , ## __VA_ARGS__) ) )
                         ^
   fs/cifs/dfs_cache.c:1270:28: note: initialize the variable 'ppath' to silence this warning
           char *target_share, *ppath;
                                     ^
                                      = NULL
   1 warning generated.


vim +1294 fs/cifs/dfs_cache.c

  1255	
  1256	/**
  1257	 * dfs_cache_get_tgt_share - parse a DFS target
  1258	 *
  1259	 * @path: DFS full path
  1260	 * @it: DFS target iterator.
  1261	 * @share: tree name.
  1262	 * @prefix: prefix path.
  1263	 *
  1264	 * Return zero if target was parsed correctly, otherwise non-zero.
  1265	 */
  1266	int dfs_cache_get_tgt_share(char *path, const struct dfs_cache_tgt_iterator *it, char **share,
  1267				    char **prefix)
  1268	{
  1269		char sep;
  1270		char *target_share, *ppath;
  1271		const char *target_ppath, *dfsref_ppath;
  1272		size_t target_pplen, dfsref_pplen;
  1273		size_t len, c;
  1274	
  1275		if (!it || !path || !share || !prefix || strlen(path) < it->it_path_consumed)
  1276			return -EINVAL;
  1277	
  1278		sep = it->it_name[0];
  1279		if (sep != '\\' && sep != '/')
  1280			return -EINVAL;
  1281	
  1282		target_ppath = parse_target_share(it->it_name, &target_share);
  1283		if (IS_ERR(target_ppath))
  1284			return PTR_ERR(target_ppath);
  1285	
  1286		/* point to prefix in DFS referral path */
  1287		dfsref_ppath = path + it->it_path_consumed;
  1288		dfsref_ppath += strspn(dfsref_ppath, "/\\");
  1289	
  1290		target_pplen = strlen(target_ppath);
  1291		dfsref_pplen = strlen(dfsref_ppath);
  1292	
  1293		/* merge prefix paths from DFS referral path and target node */
> 1294		if (target_pplen || dfsref_pplen) {
  1295			len = target_pplen + dfsref_pplen + 2;
  1296			ppath = kzalloc(len, GFP_KERNEL);
  1297			if (!ppath) {
  1298				kfree(target_share);
  1299				return -ENOMEM;
  1300			}
  1301			c = strscpy(ppath, target_ppath, len);
  1302			if (c && dfsref_pplen)
  1303				ppath[c] = sep;
  1304			strlcat(ppath, dfsref_ppath, len);
  1305		}
  1306		*share = target_share;
  1307		*prefix = ppath;
  1308		return 0;
  1309	}
  1310	

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