WARNING: Possible repeated word: 'libarena'
#72: FILE: tools/testing/selftests/bpf/Makefile:763:
+	+$(MAKE) -C libarena libarena.skel.h $(LIBARENA_MAKE_ARGS)

WARNING: Improper SPDX comment style for 'tools/testing/selftests/bpf/libarena/include/libarena/common.h', please use '/*' instead
#164: FILE: tools/testing/selftests/bpf/libarena/include/libarena/common.h:1:
+// SPDX-License-Identifier: LGPL-2.1 OR BSD-2-Clause

WARNING: Missing or malformed SPDX-License-Identifier tag in line 1
#164: FILE: tools/testing/selftests/bpf/libarena/include/libarena/common.h:1:
+// SPDX-License-Identifier: LGPL-2.1 OR BSD-2-Clause

WARNING: __always_unused or __maybe_unused is preferred over __attribute__((__unused__))
#185: FILE: tools/testing/selftests/bpf/libarena/include/libarena/common.h:22:
+#define __maybe_unused __attribute__((__unused__))

ERROR: Macros with complex values should be enclosed in parentheses
#188: FILE: tools/testing/selftests/bpf/libarena/include/libarena/common.h:25:
+#define private(name) SEC(".data." #name) __hidden __attribute__((aligned(8)))

BUT SEE:

   do {} while (0) advice is over-stated in a few situations:

   The more obvious case is macros, like MODULE_PARM_DESC, invoked at
   file-scope, where C disallows code (it must be in functions).  See
   $exceptions if you have one to add by name.

   More troublesome is declarative macros used at top of new scope,
   like DECLARE_PER_CPU.  These might just compile with a do-while-0
   wrapper, but would be incorrect.  Most of these are handled by
   detecting struct,union,etc declaration primitives in $exceptions.

   Theres also macros called inside an if (block), which "return" an
   expression.  These cannot do-while, and need a ({}) wrapper.

   Enjoy this qualification while we work to improve our heuristics.

WARNING: Prefer __aligned(8) over __attribute__((aligned(8)))
#188: FILE: tools/testing/selftests/bpf/libarena/include/libarena/common.h:25:
+#define private(name) SEC(".data." #name) __hidden __attribute__((aligned(8)))

WARNING: Use of volatile is usually wrong: see Documentation/process/volatile-considered-harmful.rst
#209: FILE: tools/testing/selftests/bpf/libarena/include/libarena/common.h:46:
+extern const volatile u32 zero;

WARNING: Improper SPDX comment style for 'tools/testing/selftests/bpf/libarena/include/libarena/userspace.h', please use '/*' instead
#249: FILE: tools/testing/selftests/bpf/libarena/include/libarena/userspace.h:1:
+// SPDX-License-Identifier: LGPL-2.1 OR BSD-2-Clause

WARNING: Missing or malformed SPDX-License-Identifier tag in line 1
#249: FILE: tools/testing/selftests/bpf/libarena/include/libarena/userspace.h:1:
+// SPDX-License-Identifier: LGPL-2.1 OR BSD-2-Clause

WARNING: line length of 81 exceeds 80 columns
#278: FILE: tools/testing/selftests/bpf/libarena/include/libarena/userspace.h:30:
+static inline int libarena_run_prog_args(int prog_fd, void *args, size_t argsize)

WARNING: Use of volatile is usually wrong: see Documentation/process/volatile-considered-harmful.rst
#358: FILE: tools/testing/selftests/bpf/libarena/src/common.bpf.c:5:
+const volatile u32 zero = 0;

total: 1 errors, 10 warnings, 0 checks, 324 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 00da74127e67 ("selftests/bpf: Add basic libarena scaffolding") 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.