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

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

WARNING: __always_unused or __maybe_unused is preferred over __attribute__((__unused__))
#162: FILE: tools/testing/selftests/bpf/libarena/include/common.h:23:
+#define __maybe_unused __attribute__((__unused__))

ERROR: Macros with complex values should be enclosed in parentheses
#165: FILE: tools/testing/selftests/bpf/libarena/include/common.h:26:
+#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)))
#165: FILE: tools/testing/selftests/bpf/libarena/include/common.h:26:
+#define private(name) SEC(".data." #name) __hidden __attribute__((aligned(8)))

WARNING: Use of volatile is usually wrong: see Documentation/process/volatile-considered-harmful.rst
#180: FILE: tools/testing/selftests/bpf/libarena/include/common.h:41:
+extern const volatile u32 zero;

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

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

CHECK: Comparison to NULL could be written "strstr"
#239: FILE: tools/testing/selftests/bpf/libarena/include/selftest_helpers.h:27:
+	return strstr(name, "test_") != NULL;

WARNING: do not add new typedefs
#326: FILE: tools/testing/selftests/bpf/libarena/selftests/selftest.c:22:
+typedef struct libarena selftest;

WARNING: line length of 85 exceeds 80 columns
#349: FILE: tools/testing/selftests/bpf/libarena/selftests/selftest.c:45:
+		while ((err = bpf_prog_stream_read(prog_fd, 1, buf, 1024, NULL)) > 0)

WARNING: line length of 85 exceeds 80 columns
#356: FILE: tools/testing/selftests/bpf/libarena/selftests/selftest.c:52:
+		while ((err = bpf_prog_stream_read(prog_fd, 2, buf, 1024, NULL)) > 0)

CHECK: Alignment should match open parenthesis
#367: FILE: tools/testing/selftests/bpf/libarena/selftests/selftest.c:63:
+static int libbpf_print_fn(enum libbpf_print_level level,
+		const char *format, va_list args)

WARNING: line length of 84 exceeds 80 columns
#404: FILE: tools/testing/selftests/bpf/libarena/selftests/selftest.c:100:
+		if (strcmp(argv[i], "-v") == 0 || strcmp(argv[i], "--verbose") == 0)

WARNING: line length of 82 exceeds 80 columns
#423: FILE: tools/testing/selftests/bpf/libarena/selftests/selftest.c:119:
+	ret = libarena_run_prog(bpf_program__fd(skel->progs.arena_alloc_reserve));

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

total: 1 errors, 13 warnings, 2 checks, 438 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 18697deee16b ("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.