CHECK: extern prototypes should be avoided in .h files
#33: FILE: tools/testing/selftests/bpf/bpf_experimental.h:599:
+extern int bpf_cgroup_read_xattr(struct cgroup *cgroup, const char *name__str,

WARNING: added, moved or deleted file(s), does MAINTAINERS need updating?
#38: 
new file mode 100644

WARNING: line length of 89 exceeds 80 columns
#158: FILE: tools/testing/selftests/bpf/prog_tests/cgroup_xattr.c:116:
+	if (!ASSERT_OK(read_cgroupfs_xattr__attach(skel), "read_cgroupfs_xattr__attach"))

WARNING: line length of 90 exceeds 80 columns
#406: FILE: tools/testing/selftests/bpf/progs/read_cgroupfs_xattr.c:49:
+		    !bpf_strncmp(xattr_value, sizeof(expected_value_a), expected_value_a))

WARNING: line length of 90 exceeds 80 columns
#409: FILE: tools/testing/selftests/bpf/progs/read_cgroupfs_xattr.c:52:
+		    !bpf_strncmp(xattr_value, sizeof(expected_value_b), expected_value_b))

total: 0 errors, 4 warnings, 1 checks, 370 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 02f1ae649bce ("selftests/bpf: Add tests for bpf_cgroup_read_xattr") 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, 4 warnings, 1 checks, 370 lines checked