Hi,

[FYI, it's a private test report for your RFC patch.]
[auto build test WARNING on v5.14-rc5]
[also build test WARNING on next-20210812]
[cannot apply to arm64/for-next/core tip/perf/core]
[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]

url:    https://github.com/0day-ci/linux/commits/madvenka-linux-microsoft-com/arm64-Make-all-stack-walking-functions-use-arch_stack_walk/20210812-222448
base:    36a21d51725af2ce0700c6ebcb6b9594aac658a6
config: arm64-allyesconfig (attached as .config)
compiler: aarch64-linux-gcc (GCC) 10.3.0
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://github.com/0day-ci/linux/commit/fcc398e417dd1c8521e069b516322c5e5f615444
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review madvenka-linux-microsoft-com/arm64-Make-all-stack-walking-functions-use-arch_stack_walk/20210812-222448
        git checkout fcc398e417dd1c8521e069b516322c5e5f615444
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-10.3.0 make.cross ARCH=arm64 

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

All warnings (new ones prefixed by >>):

>> arch/arm64/kernel/stacktrace.c:29:12: warning: no previous prototype for 'init_sym_code_functions' [-Wmissing-prototypes]
      29 | int __init init_sym_code_functions(void)
         |            ^~~~~~~~~~~~~~~~~~~~~~~


vim +/init_sym_code_functions +29 arch/arm64/kernel/stacktrace.c

    28	
  > 29	int __init init_sym_code_functions(void)
    30	{
    31		size_t size = (unsigned long)__sym_code_functions_end -
    32			      (unsigned long)__sym_code_functions_start;
    33	
    34		sym_code_functions = (struct code_range *)__sym_code_functions_start;
    35		/*
    36		 * Order it so that sym_code_functions is not visible before
    37		 * num_sym_code_functions.
    38		 */
    39		smp_mb();
    40		num_sym_code_functions = size / sizeof(struct code_range);
    41	
    42		return 0;
    43	}
    44	early_initcall(init_sym_code_functions);
    45	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all(a)lists.01.org