WARNING: line length of 81 exceeds 80 columns
#39: FILE: tools/testing/selftests/bpf/bpf_experimental.h:587:
+extern int bpf_iter_kmem_cache_new(struct bpf_iter_kmem_cache *it) __weak __ksym;

CHECK: extern prototypes should be avoided in .h files
#39: FILE: tools/testing/selftests/bpf/bpf_experimental.h:587:
+extern int bpf_iter_kmem_cache_new(struct bpf_iter_kmem_cache *it) __weak __ksym;

WARNING: line length of 97 exceeds 80 columns
#40: FILE: tools/testing/selftests/bpf/bpf_experimental.h:588:
+extern struct kmem_cache *bpf_iter_kmem_cache_next(struct bpf_iter_kmem_cache *it) __weak __ksym;

CHECK: extern prototypes should be avoided in .h files
#40: FILE: tools/testing/selftests/bpf/bpf_experimental.h:588:
+extern struct kmem_cache *bpf_iter_kmem_cache_next(struct bpf_iter_kmem_cache *it) __weak __ksym;

WARNING: line length of 86 exceeds 80 columns
#41: FILE: tools/testing/selftests/bpf/bpf_experimental.h:589:
+extern void bpf_iter_kmem_cache_destroy(struct bpf_iter_kmem_cache *it) __weak __ksym;

CHECK: extern prototypes should be avoided in .h files
#41: FILE: tools/testing/selftests/bpf/bpf_experimental.h:589:
+extern void bpf_iter_kmem_cache_destroy(struct bpf_iter_kmem_cache *it) __weak __ksym;

WARNING: line length of 95 exceeds 80 columns
#58: FILE: tools/testing/selftests/bpf/prog_tests/kmem_cache_iter.c:77:
+	ASSERT_EQ(skel->bss->open_coded_seen, skel->bss->kmem_cache_seen, "open_code_seen_eq");

WARNING: line length of 81 exceeds 80 columns
#83: FILE: tools/testing/selftests/bpf/prog_tests/kmem_cache_iter.c:93:
+	iter_fd = bpf_iter_create(bpf_link__fd(skel->links.slab_info_collector));

CHECK: Comparison to NULL could be written "!r"
#142: FILE: tools/testing/selftests/bpf/progs/kmem_cache_iter.c:102:
+		if (r == NULL)

total: 0 errors, 5 warnings, 4 checks, 104 lines checked

NOTE: For some of the reported defects, checkpatch may be able to
      mechanically convert to the typical style using --fix or --fix-inplace.

Commit fdb546120d57 ("selftests/bpf: Add a test for open coded kmem_cache iter") has style problems, please review.

NOTE: Ignored message types: ALLOC_SIZEOF_STRUCT BAD_REPORTED_BY_LINK CAMELCASE COMMIT_LOG_LONG_LINE GIT_COMMIT_ID MACRO_ARG_REUSE NO_AUTHOR_SIGN_OFF

NOTE: If any of the errors are false positives, please report
      them to the maintainer, see CHECKPATCH in MAINTAINERS.
total: 0 errors, 5 warnings, 4 checks, 104 lines checked