Re: [PATCH bpf-next v2 15/15] selftests/bpf: Add test for global data of a program in Rust

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] bpf: missing ASSERT_OK_PTR for bpf_object__find_program_by_name
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commit 3ad0a944f5e1d8b874c6e4579bc0bb7941f6ed67
Author: Alexei Starovoitov <ast@kernel.org>

selftests/bpf: Add test for global data of a program in Rust

This commit adds a test to verify how libbpf handles global data (.data,
.bss, .rodata) of a Rust BPF program within an arena. It introduces a
new Rust program and dynamically loads the resulting object file using
manual libbpf APIs in data_in_arena.c.

> diff --git a/tools/testing/selftests/bpf/prog_tests/data_in_arena.c b/tools/testing/selftests/bpf/prog_tests/data_in_arena.c
> index 86dc6798bbdef..cb1023507c017 100644
> --- a/tools/testing/selftests/bpf/prog_tests/data_in_arena.c
> +++ b/tools/testing/selftests/bpf/prog_tests/data_in_arena.c

[ ... ]

> +/* The object is there if rustc and clang can build it, see Makefile.buildvars */
> +static void test_rust(void)
> +{
> +	const char *file = "./data_in_arena_rust.bpf.o";
> +	struct bpf_object *obj;
> +
> +	if (access(file, R_OK)) {
> +		test__skip();
> +		return;
> +	}
> +	obj = bpf_object__open_file(file, NULL);
> +	if (!ASSERT_OK_PTR(obj, "open"))
> +		return;
> +	if (!ASSERT_OK(bpf_object__load(obj), "load"))
> +		goto out;
> +	/* libbpf goes on without BTF when the kernel doesn't take it */
> +	ASSERT_GE(bpf_object__btf_fd(obj), 0, "btf_fd");
> +	ASSERT_EQ(run_prog(bpf_object__find_program_by_name(obj, "list_in_data")),
> +		  100 + 20 + 3, "retval");

[Severity: Medium]
Could this result in a crash if the program is not found in the object file?

bpf_object__find_program_by_name() returns NULL if the specified program is
not found. Passing this result directly into run_prog() without prior
validation via ASSERT_OK_PTR violates the BPF selftest guidelines for
manual lookup APIs, and might cause the test to crash instead of failing
cleanly.

> +out:
> +	bpf_object__close(obj);
> +}

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20261002124714.180012-1-alexei.starovoitov@gmail.com?part=15