[vbabka:objext_split 11/14] mm/slub.c:1201:6: error: call to undeclared function 'obj_exts_in_object'; ISO C99 and later do not support implicit function declarations

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

Hi Vlastimil,

FYI, the error/warning was bisected to this commit, please ignore it if it's irrelevant.

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/vbabka/linux.git objext_split
head:   8bd682e28958694beba958e2a3af94c6e1789819
commit: 0923358e166406daf2533102ff371c4ba7f93bf3 [11/14] mm/slab: replace stride with obj_exts_in_object flag
config: um-allnoconfig (https://download.01.org/0day-ci/archive/20260709/202607091431.vgj70nrG-lkp@intel.com/config)
compiler: clang version 17.0.6 (https://github.com/llvm/llvm-project 6009708b4367171ccdbf4b5905cb6a803753fe18)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260709/202607091431.vgj70nrG-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/202607091431.vgj70nrG-lkp@intel.com/

All errors (new ones prefixed by >>):

>> mm/slub.c:1201:6: error: call to undeclared function 'obj_exts_in_object'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
    1201 |         if (obj_exts_in_object(slab))
         |             ^
   mm/slub.c:1201:6: note: did you mean 'obj_exts_in_slab'?
   mm/slub.c:865:20: note: 'obj_exts_in_slab' declared here
     865 | static inline bool obj_exts_in_slab(struct kmem_cache *s, struct slab *slab)
         |                    ^
   mm/slub.c:1406:6: error: call to undeclared function 'obj_exts_in_object'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
    1406 |         if (obj_exts_in_object(slab))
         |             ^
   mm/slub.c:1434:36: error: call to undeclared function 'obj_exts_in_object'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
    1434 |         if (obj_exts_in_slab(s, slab) && !obj_exts_in_object(slab)) {
         |                                           ^
   mm/slub.c:6502:11: error: call to undeclared function 'obj_exts_in_object'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
    6502 |         else if (obj_exts_in_object(slab))
         |                  ^
   4 errors generated.


vim +/obj_exts_in_object +1201 mm/slub.c

  1166	
  1167	static void print_trailer(struct kmem_cache *s, struct slab *slab, u8 *p)
  1168	{
  1169		unsigned int off;	/* Offset of last byte */
  1170		u8 *addr = slab_address(slab);
  1171	
  1172		print_tracking(s, p);
  1173	
  1174		print_slab_info(slab);
  1175	
  1176		pr_err("Object 0x%p @offset=%tu fp=0x%p\n\n",
  1177		       p, p - addr, get_freepointer(s, p));
  1178	
  1179		if (s->flags & SLAB_RED_ZONE)
  1180			print_section(KERN_ERR, "Redzone  ", p - s->red_left_pad,
  1181				      s->red_left_pad);
  1182		else if (p > addr + 16)
  1183			print_section(KERN_ERR, "Bytes b4 ", p - 16, 16);
  1184	
  1185		print_section(KERN_ERR,         "Object   ", p,
  1186			      min_t(unsigned int, s->object_size, PAGE_SIZE));
  1187		if (s->flags & SLAB_RED_ZONE)
  1188			print_section(KERN_ERR, "Redzone  ", p + s->object_size,
  1189				s->inuse - s->object_size);
  1190	
  1191		off = get_info_end(s);
  1192	
  1193		if (s->flags & SLAB_STORE_USER)
  1194			off += 2 * sizeof(struct track);
  1195	
  1196		if (slub_debug_orig_size(s))
  1197			off += sizeof(unsigned long);
  1198	
  1199		off += kasan_metadata_size(s, false);
  1200	
> 1201		if (obj_exts_in_object(slab))
  1202			off += sizeof(struct slabobj_ext);
  1203	
  1204		if (off != size_from_object(s))
  1205			/* Beginning of the filler is the free pointer */
  1206			print_section(KERN_ERR, "Padding  ", p + off,
  1207				      size_from_object(s) - off);
  1208	}
  1209	

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