Hi Andrii,

I love your patch! Perhaps something to improve:

[auto build test WARNING on bpf-next/master]

url:    https://github.com/0day-ci/linux/commits/Andrii-Nakryiko/Support-kernel-module-ksym-variables/20210106-144531
base:   https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master
config: x86_64-randconfig-a015-20210106 (attached as .config)
compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project 5c951623bc8965fa1e89660f2f5f4a2944e4981a)
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 x86_64 cross compiling tool for clang build
        # apt-get install binutils-x86-64-linux-gnu
        # https://github.com/0day-ci/linux/commit/1dde2eabb1a7670d0e764e46dae1ef0a9abf0466
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Andrii-Nakryiko/Support-kernel-module-ksym-variables/20210106-144531
        git checkout 1dde2eabb1a7670d0e764e46dae1ef0a9abf0466
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=x86_64 

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 >>):

   kernel/bpf/core.c:1350:12: warning: no previous prototype for function 'bpf_probe_read_kernel' [-Wmissing-prototypes]
   u64 __weak bpf_probe_read_kernel(void *dst, u32 size, const void *unsafe_ptr)
              ^
   kernel/bpf/core.c:1350:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   u64 __weak bpf_probe_read_kernel(void *dst, u32 size, const void *unsafe_ptr)
   ^
   static 
   kernel/bpf/core.c:1704:6: warning: no previous prototype for function 'bpf_patch_call_args' [-Wmissing-prototypes]
   void bpf_patch_call_args(struct bpf_insn *insn, u32 stack_depth)
        ^
   kernel/bpf/core.c:1704:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   void bpf_patch_call_args(struct bpf_insn *insn, u32 stack_depth)
   ^
   static 
   kernel/bpf/core.c:2102:6: warning: no previous prototype for function '__bpf_free_used_maps' [-Wmissing-prototypes]
   void __bpf_free_used_maps(struct bpf_prog_aux *aux,
        ^
   kernel/bpf/core.c:2102:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   void __bpf_free_used_maps(struct bpf_prog_aux *aux,
   ^
   static 
>> kernel/bpf/core.c:2122:6: warning: no previous prototype for function '__bpf_free_used_btfs' [-Wmissing-prototypes]
   void __bpf_free_used_btfs(struct bpf_prog_aux *aux,
        ^
   kernel/bpf/core.c:2122:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   void __bpf_free_used_btfs(struct bpf_prog_aux *aux,
   ^
   static 
   4 warnings generated.


vim +/__bpf_free_used_btfs +2122 kernel/bpf/core.c

  2101	
> 2102	void __bpf_free_used_maps(struct bpf_prog_aux *aux,
  2103				  struct bpf_map **used_maps, u32 len)
  2104	{
  2105		struct bpf_map *map;
  2106		u32 i;
  2107	
  2108		for (i = 0; i < len; i++) {
  2109			map = used_maps[i];
  2110			if (map->ops->map_poke_untrack)
  2111				map->ops->map_poke_untrack(map, aux);
  2112			bpf_map_put(map);
  2113		}
  2114	}
  2115	
  2116	static void bpf_free_used_maps(struct bpf_prog_aux *aux)
  2117	{
  2118		__bpf_free_used_maps(aux, aux->used_maps, aux->used_map_cnt);
  2119		kfree(aux->used_maps);
  2120	}
  2121	
> 2122	void __bpf_free_used_btfs(struct bpf_prog_aux *aux,
  2123				  struct btf_mod_pair *used_btfs, u32 len)
  2124	{
  2125	#ifdef CONFIG_BPF_SYSCALL
  2126		struct btf_mod_pair *btf_mod;
  2127		u32 i;
  2128	
  2129		for (i = 0; i < len; i++) {
  2130			btf_mod = &used_btfs[i];
  2131			if (btf_mod->module)
  2132				module_put(btf_mod->module);
  2133			btf_put(btf_mod->btf);
  2134		}
  2135	#endif
  2136	}
  2137	

---
0-DAY CI Kernel Test Service, Intel Corporation
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