On 5/3/22 10:22 AM, kernel test robot wrote:
Hi Yonghong,
I love your patch! Perhaps something to improve:
[auto build test WARNING on bpf-next/master]
url: https://github.com/intel-lab-lkp/linux/commits/Yonghong-Song/bpf-Add-64bit-enum-value-support/20220502-030301
base: https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master
config: i386-randconfig-m021 (https://download.01.org/0day-ci/archive/20220504/202205040133.jd7yTwg5-lkp@xxxxxxxxx/config )
compiler: gcc-11 (Debian 11.2.0-20) 11.2.0
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@xxxxxxxxx>
New smatch warnings:
tools/lib/bpf/relo_core.c:348 bpf_core_fields_are_compat() warn: if();
Old smatch warnings:
tools/lib/bpf/relo_core.c:349 bpf_core_fields_are_compat() warn: if();
The following change should work:
diff --git a/tools/lib/bpf/relo_core.c b/tools/lib/bpf/relo_core.c
index 1e751400427b..2c8d5292e946 100644
--- a/tools/lib/bpf/relo_core.c
+++ b/tools/lib/bpf/relo_core.c
@@ -345,9 +345,8 @@ static int bpf_core_fields_are_compat(const struct
btf *local_btf,
if (btf_is_composite(local_type) && btf_is_composite(targ_type))
return 1;
if (btf_kind(local_type) != btf_kind(targ_type)) {
- if (btf_is_enum(local_type) && btf_is_enum64(targ_type)) ;
- else if (btf_is_enum64(local_type) &&
btf_is_enum(targ_type)) ;
- else return 0;
+ if (!btf_is_enum(local_type) || !btf_is_enum64(targ_type))
+ return 0;
}
switch (btf_kind(local_type)) {
I will wait for more comments before submitting version 2.
vim +348 tools/lib/bpf/relo_core.c
314
315 /* Check two types for compatibility for the purpose of field access
316 * relocation. const/volatile/restrict and typedefs are skipped to ensure we
317 * are relocating semantically compatible entities:
318 * - any two STRUCTs/UNIONs are compatible and can be mixed;
319 * - any two FWDs are compatible, if their names match (modulo flavor suffix);
320 * - any two PTRs are always compatible;
321 * - for ENUMs, names should be the same (ignoring flavor suffix) or at
322 * least one of enums should be anonymous;
323 * - for ENUMs, check sizes, names are ignored;
324 * - for INT, size and signedness are ignored;
325 * - any two FLOATs are always compatible;
326 * - for ARRAY, dimensionality is ignored, element types are checked for
327 * compatibility recursively;
328 * - everything else shouldn't be ever a target of relocation.
329 * These rules are not set in stone and probably will be adjusted as we get
330 * more experience with using BPF CO-RE relocations.
331 */
332 static int bpf_core_fields_are_compat(const struct btf *local_btf,
333 __u32 local_id,
334 const struct btf *targ_btf,
335 __u32 targ_id)
336 {
337 const struct btf_type *local_type, *targ_type;
338
339 recur:
340 local_type = skip_mods_and_typedefs(local_btf, local_id, &local_id);
341 targ_type = skip_mods_and_typedefs(targ_btf, targ_id, &targ_id);
342 if (!local_type || !targ_type)
343 return -EINVAL;
344
345 if (btf_is_composite(local_type) && btf_is_composite(targ_type))
346 return 1;
347 if (btf_kind(local_type) != btf_kind(targ_type)) {
> 348 if (btf_is_enum(local_type) && btf_is_enum64(targ_type)) ;
349 else if (btf_is_enum64(local_type) && btf_is_enum(targ_type)) ;
350 else return 0;
351 }
352
353 switch (btf_kind(local_type)) {
354 case BTF_KIND_PTR:
355 case BTF_KIND_FLOAT:
356 return 1;
357 case BTF_KIND_FWD:
358 case BTF_KIND_ENUM:
359 case BTF_KIND_ENUM64: {
360 const char *local_name, *targ_name;
361 size_t local_len, targ_len;
362
363 local_name = btf__name_by_offset(local_btf,
364 local_type->name_off);
365 targ_name = btf__name_by_offset(targ_btf, targ_type->name_off);
366 local_len = bpf_core_essential_name_len(local_name);
367 targ_len = bpf_core_essential_name_len(targ_name);
368 /* one of them is anonymous or both w/ same flavor-less names */
369 return local_len == 0 || targ_len == 0 ||
370 (local_len == targ_len &&
371 strncmp(local_name, targ_name, local_len) == 0);
372 }
373 case BTF_KIND_INT:
374 /* just reject deprecated bitfield-like integers; all other
375 * integers are by default compatible between each other
376 */
377 return btf_int_offset(local_type) == 0 &&
378 btf_int_offset(targ_type) == 0;
379 case BTF_KIND_ARRAY:
380 local_id = btf_array(local_type)->type;
381 targ_id = btf_array(targ_type)->type;
382 goto recur;
383 default:
384 return 0;
385 }
386 }
387
