Re: [PATCH bpf-next 09/13] selftests/bpf: Add tracing_multi bpf prog attach failure tests

[Leon Hwang <leon.hwang@linux.dev>]

On 9/8/26 23:17, sashiko-bot@kernel.org wrote:
> Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
> - [Low] Build failure due to undefined symbol `libbpf_find_prog_btf_id`.
> --
> 
> --- Patch [9]: [PATCH bpf-next 09/13] selftests/bpf: Add tracing_multi bpf prog attach failure tests ---
> commit c3b104cf9a90f8ddf11f23d2944ad76004fb3150
> Author: Leon Hwang <leon.hwang@linux.dev>
> 
> selftests/bpf: Add tracing_multi bpf prog attach failure tests
> 
> This patch adds tests for tracing_multi BPF program attach failures,
> covering both libbpf and kernel failure modes.
> 
>> diff --git a/tools/testing/selftests/bpf/prog_tests/tracing_multi.c b/tools/testing/selftests/bpf/prog_tests/tracing_multi.c
>> index 5ecb751af9be7..5cf11707eaf89 100644
>> --- a/tools/testing/selftests/bpf/prog_tests/tracing_multi.c
>> +++ b/tools/testing/selftests/bpf/prog_tests/tracing_multi.c
> [ ... ]
>> +	/* fail#4 (kernel) duplicate target through different fds */
>> +	token_fd = bpf_object__token_fd(skel->obj);
>> +	token_fd = token_fd < 0 ? 0 : token_fd;
>> +	target_id = libbpf_find_prog_btf_id("target_1", fds[0], token_fd);
> 
> [Severity: Low]
> Does this code compile successfully? libbpf_find_prog_btf_id is an
> internal static function in libbpf, so calling it directly from selftests
> seems like it would cause an implicit function declaration and undefined
> reference linker error during the build.
> 

Good catch.

libbpf_find_prog_btf_id() is exposed in the patch #11.

Will move the expose in this patch.

Thanks,
Leon

>> +	if (!ASSERT_GT(target_id, 0, "target_1_btf_id"))
>> +		goto cleanup;
>> +
>> +	dup_fd = dup(fds[0]);
>> +	if (!ASSERT_GE(dup_fd, 0, "dup_target_fd"))
>> +		goto cleanup;
>