Re: [RFC bpf-next 06/13] bpf: Move kfunc definitions out of verifier.c

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

Hi Daniel,

[This is a private test report for your RFC patch.]
kernel test robot noticed the following build warnings:

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

url:    https://github.com/intel-lab-lkp/linux/commits/Daniel-Xu/bpf-Move-bpf_prog_ctx_arg_info_init-body-into-header/20250409-114116
base:   https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master
patch link:    https://lore.kernel.org/r/c73f939de0f6af022e009dda057b6f941c6fce59.1744169424.git.dxu%40dxuuu.xyz
patch subject: [RFC bpf-next 06/13] bpf: Move kfunc definitions out of verifier.c
config: arm64-randconfig-002-20250410 (https://download.01.org/0day-ci/archive/20250410/202504101343.eRiCSJes-lkp@intel.com/config)
compiler: clang version 21.0.0git (https://github.com/llvm/llvm-project 92c93f5286b9ff33f27ff694d2dc33da1c07afdd)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250410/202504101343.eRiCSJes-lkp@intel.com/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 <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202504101343.eRiCSJes-lkp@intel.com/

All warnings (new ones prefixed by >>):

   kernel/bpf/core.c:320:9: error: call to undeclared function 'btf_distill_func_proto'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
     320 |                 ret = btf_distill_func_proto(log, btf, t, tname, &tgt_info->fmodel);
         |                       ^
   kernel/bpf/core.c:339:7: error: call to undeclared function 'btf_check_type_match'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
     339 |                     btf_check_type_match(log, prog, btf, t))
         |                     ^
   kernel/bpf/core.c:396:19: error: call to undeclared function 'btf_kfunc_is_modify_return'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
     396 |                                         u32 *flags = btf_kfunc_is_modify_return(btf, btf_id,
         |                                                      ^
   kernel/bpf/core.c:396:11: error: incompatible integer to pointer conversion initializing 'u32 *' (aka 'unsigned int *') with an expression of type 'int' [-Wint-conversion]
     396 |                                         u32 *flags = btf_kfunc_is_modify_return(btf, btf_id,
         |                                              ^       ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
     397 |                                                                                 prog);
         |                                                                                 ~~~~~
   kernel/bpf/core.c:425:8: error: call to undeclared function 'btf_kfunc_is_modify_return'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
     425 |                         if (btf_kfunc_is_modify_return(btf, btf_id, prog) ||
         |                             ^
   kernel/bpf/core.c:1638:33: error: use of undeclared identifier 'kfunc_desc_cmp_by_id_off'
    1638 |                        sizeof(tab->descs[0]), kfunc_desc_cmp_by_id_off);
         |                                               ^
>> kernel/bpf/core.c:1628:1: warning: no previous prototype for function 'find_kfunc_desc' [-Wmissing-prototypes]
    1628 | find_kfunc_desc(const struct bpf_prog *prog, u32 func_id, u16 offset)
         | ^
   kernel/bpf/core.c:1627:7: note: declare 'static' if the function is not intended to be used outside of this translation unit
    1627 | const struct bpf_kfunc_desc *
         |       ^
         | static 
   kernel/bpf/core.c:1642:5: error: redefinition of 'bpf_get_kfunc_addr'
    1642 | int bpf_get_kfunc_addr(const struct bpf_prog *prog, u32 func_id,
         |     ^
   include/linux/bpf.h:3084:1: note: previous definition is here
    3084 | bpf_get_kfunc_addr(const struct bpf_prog *prog, u32 func_id,
         | ^
   1 warning and 7 errors generated.


vim +/find_kfunc_desc +1628 kernel/bpf/core.c

  1626	
  1627	const struct bpf_kfunc_desc *
> 1628	find_kfunc_desc(const struct bpf_prog *prog, u32 func_id, u16 offset)
  1629	{
  1630		struct bpf_kfunc_desc desc = {
  1631			.func_id = func_id,
  1632			.offset = offset,
  1633		};
  1634		struct bpf_kfunc_desc_tab *tab;
  1635	
  1636		tab = prog->aux->kfunc_tab;
  1637		return bsearch(&desc, tab->descs, tab->nr_descs,
  1638			       sizeof(tab->descs[0]), kfunc_desc_cmp_by_id_off);
  1639	}
  1640	EXPORT_SYMBOL_GPL(find_kfunc_desc);
  1641	

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