Re: [PATCH bpf-next 1/4] libarena: remove in-code licenses

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] selftests/bpf: missing license section in libarena_bench.bpf.o
--

commit 1bfbb56cf90063a6a767e7e64926692dd815ff9b
Author: Emil Tsalapatis <emil@etsalapatis.com>

libarena: remove in-code licenses

This commit removes the SEC("license") definitions from the libarena BPF
source files (asan.bpf.c, buddy.bpf.c, and common.bpf.c) so that consumers
of libarena provide their own license section.

> diff --git a/tools/testing/selftests/bpf/libarena/src/asan.bpf.c b/tools/testing/selftests/bpf/libarena/src/asan.bpf.c
> index de656b69d13af..8a0f061106064 100644
> --- a/tools/testing/selftests/bpf/libarena/src/asan.bpf.c
> +++ b/tools/testing/selftests/bpf/libarena/src/asan.bpf.c
> @@ -532,5 +532,3 @@ __weak __noasan int asan_init(struct asan_init_args *args)
>  #pragma clang attribute pop
>  
>  #endif /* BPF_ARENA_ASAN */
> -
> -__weak char _license[] SEC("license") = "GPL";
> diff --git a/tools/testing/selftests/bpf/libarena/src/buddy.bpf.c b/tools/testing/selftests/bpf/libarena/src/buddy.bpf.c
> index 2490ab1396de0..552ce87875e3b 100644
> --- a/tools/testing/selftests/bpf/libarena/src/buddy.bpf.c
> +++ b/tools/testing/selftests/bpf/libarena/src/buddy.bpf.c
> @@ -899,5 +899,3 @@ __weak int buddy_free(struct buddy __arena *buddy, void __arena *addr)
>  
>  	return ret;
>  }
> -
> -__weak char _license[] SEC("license") = "GPL";
> diff --git a/tools/testing/selftests/bpf/libarena/src/common.bpf.c b/tools/testing/selftests/bpf/libarena/src/common.bpf.c
> index d1af60b818389..d859bd538c52d 100644
> --- a/tools/testing/selftests/bpf/libarena/src/common.bpf.c
> +++ b/tools/testing/selftests/bpf/libarena/src/common.bpf.c
> @@ -85,5 +85,3 @@ __weak void arena_free(void __arena *ptr)
>  {
>  	buddy_free(&buddy, ptr);
>  }
> -
> -char _license[] SEC("license") = "GPL";

[Severity: Medium]
Does removing _license from common.bpf.c, buddy.bpf.c, and asan.bpf.c leave
libarena_bench.bpf.o without a license section and break the libarena
benchmarks at load time?

In tools/testing/selftests/bpf/libarena/Makefile, libarena_bench.bpf.o is
linked solely from LIBARENA_CORE_SOURCES and LIBARENA_BENCH_SOURCES:

    LIBARENA_BENCH_OBJECTS = $(notdir $(LIBARENA_CORE_SOURCES:.bpf.c=.bpf.o) \
                                      $(LIBARENA_BENCH_SOURCES:.bpf.c=.bpf.o))

Unlike the selftests in selftests/test_buddy.bpf.c and
selftests/test_asan_buddy.bpf.c, the benchmark source in
tools/testing/selftests/bpf/libarena/benchs/bench_malloc.bpf.c does not
define a SEC("license") section.

When running the libarena-malloc or libarena-calloc benchmarks in
tools/testing/selftests/bpf/benchs/bench_libarena.c:

    malloc_setup() / calloc_setup()
      -> setup_common()
           -> libarena_bench__open_and_load()

libarena_bench.bpf.o now loads with an empty license string, so the BPF
verifier rejects the programs with -EINVAL when checking GPL compatibility
for their kfunc calls, kernel BTF accesses, and bpf_trace_printk usage.

Should tools/testing/selftests/bpf/libarena/benchs/bench_malloc.bpf.c define
a SEC("license") section now that the core library sources no longer provide
one?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20261027162916.10996-1-emil@etsalapatis.com?part=1