Re: [PATCH bpf-next v4 3/3] selftests/bpf: Add test for using css_task iter in sleepable progs

[Yonghong Song <yonghong.song@xxxxxxxxx>]

On 10/30/23 10:04 PM, Chuyi Zhou wrote:
> This Patch add a test to prove css_task iter can be used in normal
> sleepable progs.
>
> Signed-off-by: Chuyi Zhou <zhouchuyi@xxxxxxxxxxxxx>

Acked-by: Yonghong Song <yonghong.song@xxxxxxxxx>

> ---
>   .../testing/selftests/bpf/prog_tests/iters.c  |  1 +
>   .../selftests/bpf/progs/iters_css_task.c      | 19 +++++++++++++++++++
>   2 files changed, 20 insertions(+)
>
> diff --git a/tools/testing/selftests/bpf/prog_tests/iters.c b/tools/testing/selftests/bpf/prog_tests/iters.c
> index c2425791c923..bf84d4a1d9ae 100644
> --- a/tools/testing/selftests/bpf/prog_tests/iters.c
> +++ b/tools/testing/selftests/bpf/prog_tests/iters.c
> @@ -294,6 +294,7 @@ void test_iters(void)
>   	RUN_TESTS(iters_state_safety);
>   	RUN_TESTS(iters_looping);
>   	RUN_TESTS(iters);
> +	RUN_TESTS(iters_css_task);
>   
>   	if (env.has_testmod)
>   		RUN_TESTS(iters_testmod_seq);
> diff --git a/tools/testing/selftests/bpf/progs/iters_css_task.c b/tools/testing/selftests/bpf/progs/iters_css_task.c
> index 384ff806990f..e180aa1b1d52 100644
> --- a/tools/testing/selftests/bpf/progs/iters_css_task.c
> +++ b/tools/testing/selftests/bpf/progs/iters_css_task.c
> @@ -89,3 +89,22 @@ int cgroup_id_printer(struct bpf_iter__cgroup *ctx)
>   	bpf_cgroup_release(acquired);
>   	return 0;
>   }
> +
> +SEC("?fentry.s/" SYS_PREFIX "sys_getpgid")
> +int BPF_PROG(iter_css_task_for_each_sleep)
> +{
> +	u64 cgrp_id = bpf_get_current_cgroup_id();
> +	struct cgroup *cgrp = bpf_cgroup_from_id(cgrp_id);
> +	struct cgroup_subsys_state *css;
> +	struct task_struct *task;
> +
> +	if (cgrp == NULL)
> +		return 0;
> +	css = &cgrp->self;
> +
> +	bpf_for_each(css_task, task, css, CSS_TASK_ITER_PROCS) {
> +
> +	}
> +	bpf_cgroup_release(cgrp);
> +	return 0;
> +}