Re: [PATCH v6 2/4] selftests: bpf: add bpf_cpumask_populate selftests

Hou Tao
2025-03-08T01:37:59Z

Hi,

On 3/7/2025 11:38 PM, Emil Tsalapatis wrote:
> Add selftests for the bpf_cpumask_populate helper that sets a
> bpf_cpumask to a bit pattern provided by a BPF program.
>
> Signed-off-by: Emil Tsalapatis (Meta) <emil@etsalapatis.com>
> ---
> .../selftests/bpf/prog_tests/cpumask.c | 3 +
> .../selftests/bpf/progs/cpumask_common.h | 1 +
> .../selftests/bpf/progs/cpumask_failure.c | 38 ++++++
> .../selftests/bpf/progs/cpumask_success.c | 110 ++++++++++++++++++
> 4 files changed, 152 insertions(+)
>
> diff --git a/tools/testing/selftests/bpf/prog_tests/cpumask.c b/tools/testing/selftests/bpf/prog_tests/cpumask.c
> index e58a04654238..9b09beba988b 100644
> --- a/tools/testing/selftests/bpf/prog_tests/cpumask.c
> +++ b/tools/testing/selftests/bpf/prog_tests/cpumask.c
> @@ -25,6 +25,9 @@ static const char * const cpumask_success_testcases[] = {
> "test_global_mask_nested_deep_rcu",
> "test_global_mask_nested_deep_array_rcu",
> "test_cpumask_weight",
> + "test_populate_reject_small_mask",
> + "test_populate_reject_unaligned",
> + "test_populate",
> };
>
> static void verify_success(const char *prog_name)
> diff --git a/tools/testing/selftests/bpf/progs/cpumask_common.h b/tools/testing/selftests/bpf/progs/cpumask_common.h
> index 4ece7873ba60..86085b79f5ca 100644
> --- a/tools/testing/selftests/bpf/progs/cpumask_common.h
> +++ b/tools/testing/selftests/bpf/progs/cpumask_common.h
> @@ -61,6 +61,7 @@ u32 bpf_cpumask_any_distribute(const struct cpumask *src) __ksym __weak;
> u32 bpf_cpumask_any_and_distribute(const struct cpumask *src1,
> const struct cpumask *src2) __ksym __weak;
> u32 bpf_cpumask_weight(const struct cpumask *cpumask) __ksym __weak;
> +int bpf_cpumask_populate(struct cpumask *cpumask, void *src, size_t src__sz) __ksym __weak;
>
> void bpf_rcu_read_lock(void) __ksym __weak;
> void bpf_rcu_read_unlock(void) __ksym __weak;
> diff --git a/tools/testing/selftests/bpf/progs/cpumask_failure.c b/tools/testing/selftests/bpf/progs/cpumask_failure.c
> index b40b52548ffb..8a2fd596c8a3 100644
> --- a/tools/testing/selftests/bpf/progs/cpumask_failure.c
> +++ b/tools/testing/selftests/bpf/progs/cpumask_failure.c
> @@ -222,3 +222,41 @@ int BPF_PROG(test_invalid_nested_array, struct task_struct *task, u64 clone_flag
>
> return 0;
> }
> +
> +SEC("tp_btf/task_newtask")
> +__failure __msg("type=scalar expected=fp")
> +int BPF_PROG(test_populate_invalid_destination, struct task_struct *task, u64 clone_flags)
> +{
> + struct bpf_cpumask *invalid = (struct bpf_cpumask *)0x123456;
> + u64 bits;
> + int ret;
> +
> + ret = bpf_cpumask_populate((struct cpumask *)invalid, &bits, sizeof(bits));
> + if (!ret)
> + err = 2;
> +
> + return 0;
> +}
> +
> +SEC("tp_btf/task_newtask")
> +__failure __msg("leads to invalid memory access")
> +int BPF_PROG(test_populate_invalid_source, struct task_struct *task, u64 clone_flags)
> +{
> + void *garbage = (void *)0x123456;
> + struct bpf_cpumask *local;
> + int ret;
> +
> + local = create_cpumask();
> + if (!local) {
> + err = 1;
> + return 0;
> + }
> +
> + ret = bpf_cpumask_populate((struct cpumask *)local, garbage, 8);
> + if (!ret)
> + err = 2;
> +
> + bpf_cpumask_release(local);
> +
> + return 0;
> +}
> diff --git a/tools/testing/selftests/bpf/progs/cpumask_success.c b/tools/testing/selftests/bpf/progs/cpumask_success.c
> index 80ee469b0b60..23ef2737af50 100644
> --- a/tools/testing/selftests/bpf/progs/cpumask_success.c
> +++ b/tools/testing/selftests/bpf/progs/cpumask_success.c
> @@ -770,3 +770,113 @@ int BPF_PROG(test_refcount_null_tracking, struct task_struct *task, u64 clone_fl
> bpf_cpumask_release(mask2);
> return 0;
> }
> +
> +SEC("tp_btf/task_newtask")
> +int BPF_PROG(test_populate_reject_small_mask, struct task_struct *task, u64 clone_flags)
> +{
> + struct bpf_cpumask *local;
> + u8 toofewbits;
> + int ret;
> +

Sorry for bringing up it so later. It seems it is better to add an
is_test_task() check for these success tests.