CHECK: Please don't use multiple blank lines
#36: FILE: tools/testing/selftests/bpf/prog_tests/map_deadlock.c:10:
+
+

WARNING: line length of 84 exceeds 80 columns
#37: FILE: tools/testing/selftests/bpf/prog_tests/map_deadlock.c:11:
+static int perf_open_all_cpus(struct perf_event_attr *attr, int fds[], int max_cpus)

WARNING: line length of 84 exceeds 80 columns
#42: FILE: tools/testing/selftests/bpf/prog_tests/map_deadlock.c:16:
+		int fd = syscall(__NR_perf_event_open, attr, -1 /* pid: all */, cpu,

WARNING: Use of volatile is usually wrong: see Documentation/process/volatile-considered-harmful.rst
#193: FILE: tools/testing/selftests/bpf/progs/map_deadlock.c:25:
+const volatile int map_index;

WARNING: From:/Signed-off-by: email address mismatch: 'From: Menglong Dong <menglong8.dong@gmail.com>' != 'Signed-off-by: Menglong Dong <dongml2@chinatelecom.cn>'

total: 0 errors, 4 warnings, 1 checks, 188 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 02fdcf08bdc7 ("selftests/bpf: test map deadlock caused by NMI") has style problems, please review.

NOTE: Ignored message types: ALLOC_SIZEOF_STRUCT BAD_REPORTED_BY_LINK CAMELCASE COMMIT_LOG_LONG_LINE FILE_PATH_CHANGES 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, 188 lines checked