Re: [PATCH bpf v2 2/2] selftests/bpf: add get_next_key boundary test for cgroup_storage

[Paul Chaignon <paul.chaignon@gmail.com>]

On Fri, Apr 03, 2026 at 09:29:51PM +0800, Weiming Shi wrote:
> Verify that bpf_map__get_next_key() correctly returns -ENOENT when
> called on the last (and only) key in a cgroup_storage map. Before the
> fix in the previous patch, this would succeed with bogus key data
> instead of failing.
> 
> Suggested-by: Paul Chaignon <paul.chaignon@gmail.com>
> Signed-off-by: Weiming Shi <bestswngs@gmail.com>

Acked-by: Paul Chaignon <paul.chaignon@gmail.com>

> ---
>  tools/testing/selftests/bpf/prog_tests/cgroup_storage.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/tools/testing/selftests/bpf/prog_tests/cgroup_storage.c b/tools/testing/selftests/bpf/prog_tests/cgroup_storage.c
> index cf395715ced47..5451a43b3563e 100644
> --- a/tools/testing/selftests/bpf/prog_tests/cgroup_storage.c
> +++ b/tools/testing/selftests/bpf/prog_tests/cgroup_storage.c
> @@ -86,6 +86,11 @@ void test_cgroup_storage(void)
>  	err = SYS_NOFAIL(PING_CMD);
>  	ASSERT_OK(err, "sixth ping");
>  
> +	err = bpf_map__get_next_key(skel->maps.cgroup_storage, &key, &key,
> +				    sizeof(key));
> +	ASSERT_ERR(err, "bpf_map__get_next_key should fail");
> +	ASSERT_EQ(errno, ENOENT, "no second key");
> +
>  cleanup_progs:
>  	cgroup_storage__destroy(skel);
>  cleanup_network:
> -- 
> 2.43.0
>