Hi Steven,

kernel test robot noticed the following build warnings:

[auto build test WARNING on linus/master]
[also build test WARNING on v6.13-rc6 next-20250110]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    
https://github.com/intel-lab-lkp/linux/commits/Steven-Rostedt/ftrace-Implement-mod-cache-filtering-on-kernel-command-line/20250110-064649
base:   linus/master
patch link:    
https://lore.kernel.org/r/20250109174639.32e6f43a%40gandalf.local.home
patch subject: [PATCH] ftrace: Implement :mod: cache filtering on kernel 
command line
config: i386-randconfig-013-20250111 
(https://download.01.org/0day-ci/archive/20250111/[email protected]/config)
compiler: clang version 19.1.3 (https://github.com/llvm/llvm-project 
ab51eccf88f5321e7c60591c5546b254b6afab99)
reproduce (this is a W=1 build): 
(https://download.01.org/0day-ci/archive/20250111/[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 >>):

>> kernel/trace/ftrace.c:6232:6: warning: variable 'mod' is used uninitialized 
>> whenever 'if' condition is false [-Wsometimes-uninitialized]
    6232 |         if (next) {
         |             ^~~~
   kernel/trace/ftrace.c:6246:67: note: uninitialized use occurs here
    6246 |         ret = ftrace_set_hash(ops, func, len, NULL, 0, 0, reset, 
enable, mod);
         |                                                                      
    ^~~
   kernel/trace/ftrace.c:6232:2: note: remove the 'if' if its condition is 
always true
    6232 |         if (next) {
         |         ^~~~~~~~~
   kernel/trace/ftrace.c:6224:11: note: initialize the variable 'mod' to 
silence this warning
    6224 |         char *mod, *func, *command, *next = buf;
         |                  ^
         |                   = NULL
   1 warning generated.


vim +6232 kernel/trace/ftrace.c

  6219  
  6220  static int
  6221  ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
  6222                   int reset, int enable)
  6223  {
  6224          char *mod, *func, *command, *next = buf;
  6225          char *tmp __free(kfree) = NULL;
  6226          struct trace_array *tr = ops->private;
  6227          int ret;
  6228  
  6229          func = strsep(&next, ":");
  6230  
  6231          /* This can also handle :mod: parsing */
> 6232          if (next) {
  6233                  if (!tr)
  6234                          return -EINVAL;
  6235  
  6236                  command = strsep(&next, ":");
  6237                  if (strcmp(command, "mod") != 0)
  6238                          return -EINVAL;
  6239  
  6240                  mod = next;
  6241                  len = command - func;
  6242                  /* Save the original func as ftrace_set_hash() can 
modify it */
  6243                  tmp = kstrdup(func, GFP_KERNEL);
  6244          }
  6245  
  6246          ret = ftrace_set_hash(ops, func, len, NULL, 0, 0, reset, 
enable, mod);
  6247  
  6248          if (tr && mod && ret < 0) {
  6249                  /* Did tmp fail to allocate? */
  6250                  if (!tmp)
  6251                          return -ENOMEM;
  6252                  ret = cache_mod(tr, tmp, mod, enable);
  6253          }
  6254  
  6255          return ret;
  6256  }
  6257  

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

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