Re: [PATCH bpf-next v2 1/5] selftests/bpf: Replace CHECK with ASSERT macros for ksyms test

[Yonghong Song <yonghong.song@linux.dev>]

On 3/22/24 9:48 AM, Andrii Nakryiko wrote:
> On Fri, Mar 22, 2024 at 9:41 AM Yonghong Song <yonghong.song@linux.dev> wrote:
>>
>> On 3/22/24 9:13 AM, Andrii Nakryiko wrote:
>>> On Thu, Mar 21, 2024 at 1:01 PM Yonghong Song <yonghong.song@linux.dev> wrote:
>>>> I am going to modify ksyms test later so take this opportunity
>>>> to replace old CHECK macros with new ASSERT macros.
>>>> No functionality change.
>>>>
>>>> Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
>>>> ---
>>>>    .../testing/selftests/bpf/prog_tests/ksyms.c  | 30 ++++++-------------
>>>>    1 file changed, 9 insertions(+), 21 deletions(-)
>>>>
>>>> diff --git a/tools/testing/selftests/bpf/prog_tests/ksyms.c b/tools/testing/selftests/bpf/prog_tests/ksyms.c
>>>> index b295969b263b..6a86d1f07800 100644
>>>> --- a/tools/testing/selftests/bpf/prog_tests/ksyms.c
>>>> +++ b/tools/testing/selftests/bpf/prog_tests/ksyms.c
>>>> @@ -5,8 +5,6 @@
>>>>    #include "test_ksyms.skel.h"
>>>>    #include <sys/stat.h>
>>>>
>>>> -static int duration;
>>>> -
>>>>    void test_ksyms(void)
>>>>    {
>>>>           const char *btf_path = "/sys/kernel/btf/vmlinux";
>>>> @@ -18,43 +16,33 @@ void test_ksyms(void)
>>>>           int err;
>>>>
>>>>           err = kallsyms_find("bpf_link_fops", &link_fops_addr);
>>>> -       if (CHECK(err == -EINVAL, "kallsyms_fopen", "failed to open: %d\n", errno))
>>>> -               return;
>>>> -       if (CHECK(err == -ENOENT, "ksym_find", "symbol 'bpf_link_fops' not found\n"))
>>>> +       if (!ASSERT_TRUE(err != -EINVAL && err != -ENOENT, "bpf_link_fops"))
>>>>                   return;
>>> it's best to keep each individual equality test as ASSERT_EQ(), that
>>> way we get more specific and detailed error (with expected vs actual
>>> value), which here we'll just get "wanted true but got false", and
>>> then we'd have to debug some more which of the conditions it is. So
>>> please keep the original granularity of checks everywhere.
>> Do you mean
>>
>>           if (ASSERT_EQ(err, -EINVAL, "..."))
>>                   return;
>>           if (ASSERT_EQ(err, -ENOENT, "..."))
>>                   return;
>>
>> This does not really work, for example if err = 0, it will declare test
>> failure.
>
> if (!ASSERT_NEQ(err, -EINVAL, "..."))
>      return;
> if (!ASSERT_NEQ(err, -NOENT, "..."))
>      return;
>
> It's mirroring original logic. We had two independent checks there? In
> this case the condition is "not equal" (ASSERT_NEQ).

I actually tried this as well when I am experimenting ASSERT_EQ
and somehow I concluded that !ASSERT_NEQ not working either.

Now, I actully tried with adding err = 0, -EINVAL and -ENOENT
and verified it indeed works. I don't know how I concluded
it was not working before... Sad.

>
>>
>>>>           err = kallsyms_find("__per_cpu_start", &per_cpu_start_addr);
>>>> -       if (CHECK(err == -EINVAL, "kallsyms_fopen", "failed to open: %d\n", errno))
>>>> -               return;
>>>> -       if (CHECK(err == -ENOENT, "ksym_find", "symbol 'per_cpu_start' not found\n"))
>>>> +       if (!ASSERT_TRUE(err != -EINVAL && err != -ENOENT, "__per_cpu_start"))
>>>>                   return;
>>>>
>>>> -       if (CHECK(stat(btf_path, &st), "stat_btf", "err %d\n", errno))
>>>> +       if (!ASSERT_OK(stat(btf_path, &st), "stat_btf"))
>>>>                   return;
>>>>           btf_size = st.st_size;
>>>>
>>>>           skel = test_ksyms__open_and_load();
>>>> -       if (CHECK(!skel, "skel_open", "failed to open and load skeleton\n"))
>>>> +       if (!ASSERT_OK_PTR(skel, "test_ksyms__open_and_load"))
>>>>                   return;
>>>>
>>>>           err = test_ksyms__attach(skel);
>>>> -       if (CHECK(err, "skel_attach", "skeleton attach failed: %d\n", err))
>>>> +       if (!ASSERT_OK(err, "test_ksyms__attach"))
>>>>                   goto cleanup;
>>>>
>>>>           /* trigger tracepoint */
>>>>           usleep(1);
>>>>
>>>>           data = skel->data;
>>>> -       CHECK(data->out__bpf_link_fops != link_fops_addr, "bpf_link_fops",
>>>> -             "got 0x%llx, exp 0x%llx\n",
>>>> -             data->out__bpf_link_fops, link_fops_addr);
>>>> -       CHECK(data->out__bpf_link_fops1 != 0, "bpf_link_fops1",
>>>> -             "got %llu, exp %llu\n", data->out__bpf_link_fops1, (__u64)0);
>>>> -       CHECK(data->out__btf_size != btf_size, "btf_size",
>>>> -             "got %llu, exp %llu\n", data->out__btf_size, btf_size);
>>>> -       CHECK(data->out__per_cpu_start != per_cpu_start_addr, "__per_cpu_start",
>>>> -             "got %llu, exp %llu\n", data->out__per_cpu_start,
>>>> -             per_cpu_start_addr);
>>>> +       ASSERT_EQ(data->out__bpf_link_fops, link_fops_addr, "bpf_link_fops");
>>>> +       ASSERT_EQ(data->out__bpf_link_fops1, 0, "bpf_link_fops1");
>>>> +       ASSERT_EQ(data->out__btf_size, btf_size, "btf_size");
>>>> +       ASSERT_EQ(data->out__per_cpu_start, per_cpu_start_addr, "__per_cpu_start");
>>>>
>>>>    cleanup:
>>>>           test_ksyms__destroy(skel);
>>>> --
>>>> 2.43.0
>>>>