tree:   https://git.kernel.org/pub/scm/linux/kernel/git/jolsa/perf.git bpf/tracing_multi_ng_4
head:   e3fa3b908cc734f85477c07a0ba93480bd80702c
commit: cc9f575e0ba512afd99a1f04813be0737fe02500 [11/23] ftrace: Factor list functions for ftrace_direct_func find and alloc
config: s390-allyesconfig
compiler: s390-linux-gcc (GCC) 12.1.0
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
        # https://git.kernel.org/pub/scm/linux/kernel/git/jolsa/perf.git/commit/?id=cc9f575e0ba512afd99a1f04813be0737fe02500
        git remote add jolsa-perf https://git.kernel.org/pub/scm/linux/kernel/git/jolsa/perf.git
        git fetch --no-tags jolsa-perf bpf/tracing_multi_ng_4
        git checkout cc9f575e0ba512afd99a1f04813be0737fe02500
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=s390 SHELL=/bin/bash kernel/trace/

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 >>):

   kernel/trace/ftrace.c:295:5: warning: no previous prototype for '__register_ftrace_function' [-Wmissing-prototypes]
     295 | int __register_ftrace_function(struct ftrace_ops *ops)
         |     ^~~~~~~~~~~~~~~~~~~~~~~~~~
   kernel/trace/ftrace.c:338:5: warning: no previous prototype for '__unregister_ftrace_function' [-Wmissing-prototypes]
     338 | int __unregister_ftrace_function(struct ftrace_ops *ops)
         |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
   kernel/trace/ftrace.c:4016:15: warning: no previous prototype for 'arch_ftrace_match_adjust' [-Wmissing-prototypes]
    4016 | char * __weak arch_ftrace_match_adjust(char *str, const char *search)
         |               ^~~~~~~~~~~~~~~~~~~~~~~~
>> kernel/trace/ftrace.c:5231:1: warning: no previous prototype for 'ftrace_find_direct_func_list' [-Wmissing-prototypes]
    5231 | ftrace_find_direct_func_list(struct ftrace_direct_list *list, unsigned long addr)
         | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~


vim +/ftrace_find_direct_func_list +5231 kernel/trace/ftrace.c

  5216	
  5217	/**
  5218	 * ftrace_find_direct_func - test an address if it is a registered direct caller
  5219	 * @addr: The address of a registered direct caller
  5220	 *
  5221	 * This searches to see if a ftrace direct caller has been registered
  5222	 * at a specific address, and if so, it returns a descriptor for it.
  5223	 *
  5224	 * This can be used by architecture code to see if an address is
  5225	 * a direct caller (trampoline) attached to a fentry/mcount location.
  5226	 * This is useful for the function_graph tracer, as it may need to
  5227	 * do adjustments if it traced a location that also has a direct
  5228	 * trampoline attached to it.
  5229	 */
  5230	struct ftrace_direct_func *
> 5231	ftrace_find_direct_func_list(struct ftrace_direct_list *list, unsigned long addr)
  5232	{
  5233		struct ftrace_direct_func *entry;
  5234		bool found = false;
  5235	
  5236		/* May be called by fgraph trampoline (protected by rcu tasks) */
  5237		list_for_each_entry_rcu(entry, &list->funcs, next) {
  5238			if (entry->addr == addr) {
  5239				found = true;
  5240				break;
  5241			}
  5242		}
  5243		if (found)
  5244			return entry;
  5245	
  5246		return NULL;
  5247	}
  5248	

-- 
0-DAY CI Kernel Test Service
https://01.org/lkp