On Fri, Jun 3, 2022 at 7:11 AM Eduard Zingerman <eddyz87@xxxxxxxxx> wrote:
>
> Two new test BPF programs for test_prog selftests checking bpf_loop
> behavior. Both are corner cases for bpf_loop inlinig transformation:
> - check that bpf_loop behaves correctly when callback function is not
> a compile time constant
> - check that local function variables are not affected by allocating
> additional stack storage for registers spilled by loop inlining
>
> Signed-off-by: Eduard Zingerman <eddyz87@xxxxxxxxx>
Acked-by: Song Liu <songliubraving@xxxxxx>
With some nitpick below.
[...]
> +static void check_stack(struct bpf_loop *skel)
> +{
> + const int max_key = 12;
> + struct bpf_link *link = bpf_program__attach(skel->progs.stack_check);
> + int map_fd;
> +
> + if (!ASSERT_OK_PTR(link, "link"))
> + return;
> +
> + map_fd = bpf_map__fd(skel->maps.map1);
> +
> + if (!ASSERT_GE(map_fd, 0, "bpf_map__fd"))
> + goto out;
> +
> + for (int key = 1; key <= max_key; ++key) {
Let's move the definition of i to the beginning of the function.
> + int val = key;
> + int err = bpf_map_update_elem(map_fd, &key, &val, BPF_NOEXIST);
> +
> + if (!ASSERT_OK(err, "bpf_map_update_elem"))
> + goto out;
> + }
> +
> + usleep(1);
> +
> + for (int key = 1; key <= max_key; ++key) {
ditto.
> + int val;
> + int err = bpf_map_lookup_elem(map_fd, &key, &val);
> +
> + if (!ASSERT_OK(err, "bpf_map_lookup_elem"))
> + goto out;
> + if (!ASSERT_EQ(val, key + 1, "bad value in the map"))
> + goto out;
> + }
> +
> +out:
> + bpf_link__destroy(link);
> +}
> +
[...]
