Re: [PATCH v2 bpf] lib/buildid: handle memfd_secret() files in build_id_parse()

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

Hi Andrii,

kernel test robot noticed the following build errors:

[auto build test ERROR on bpf/master]

url:    https://github.com/intel-lab-lkp/linux/commits/Andrii-Nakryiko/lib-buildid-handle-memfd_secret-files-in-build_id_parse/20241017-061747
base:   https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf.git master
patch link:    https://lore.kernel.org/r/20241016221629.1043883-1-andrii%40kernel.org
patch subject: [PATCH v2 bpf] lib/buildid: handle memfd_secret() files in build_id_parse()
config: s390-allnoconfig (https://download.01.org/0day-ci/archive/20241017/202410171803.RRmMX9xL-lkp@intel.com/config)
compiler: clang version 20.0.0git (https://github.com/llvm/llvm-project bfe84f7085d82d06d61c632a7bad1e692fd159e4)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20241017/202410171803.RRmMX9xL-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/202410171803.RRmMX9xL-lkp@intel.com/

All errors (new ones prefixed by >>):

   In file included from lib/buildid.c:5:
   In file included from include/linux/elf.h:6:
   In file included from arch/s390/include/asm/elf.h:181:
   In file included from arch/s390/include/asm/mmu_context.h:11:
   In file included from arch/s390/include/asm/pgalloc.h:18:
   In file included from include/linux/mm.h:2213:
   include/linux/vmstat.h:518:36: warning: arithmetic between different enumeration types ('enum node_stat_item' and 'enum lru_list') [-Wenum-enum-conversion]
     518 |         return node_stat_name(NR_LRU_BASE + lru) + 3; // skip "nr_"
         |                               ~~~~~~~~~~~ ^ ~~~
>> lib/buildid.c:79:7: error: call to undeclared function 'kernel_page_present'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
      79 |             !kernel_page_present(&r->folio->page) ||
         |              ^
   1 warning and 1 error generated.


vim +/kernel_page_present +79 lib/buildid.c

    58	
    59	static int freader_get_folio(struct freader *r, loff_t file_off)
    60	{
    61		/* check if we can just reuse current folio */
    62		if (r->folio && file_off >= r->folio_off &&
    63		    file_off < r->folio_off + folio_size(r->folio))
    64			return 0;
    65	
    66		freader_put_folio(r);
    67	
    68		r->folio = filemap_get_folio(r->file->f_mapping, file_off >> PAGE_SHIFT);
    69	
    70		/* if sleeping is allowed, wait for the page, if necessary */
    71		if (r->may_fault && (IS_ERR(r->folio) || !folio_test_uptodate(r->folio))) {
    72			filemap_invalidate_lock_shared(r->file->f_mapping);
    73			r->folio = read_cache_folio(r->file->f_mapping, file_off >> PAGE_SHIFT,
    74						    NULL, r->file);
    75			filemap_invalidate_unlock_shared(r->file->f_mapping);
    76		}
    77	
    78		if (IS_ERR(r->folio) ||
  > 79		    !kernel_page_present(&r->folio->page) ||
    80		    !folio_test_uptodate(r->folio)) {
    81			if (!IS_ERR(r->folio))
    82				folio_put(r->folio);
    83			r->folio = NULL;
    84			return -EFAULT;
    85		}
    86	
    87		r->folio_off = folio_pos(r->folio);
    88		r->addr = kmap_local_folio(r->folio, 0);
    89	
    90		return 0;
    91	}
    92	

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