Re: [PATCH bpf-next 2/2] selftests/bpf: Add a test where map key_type_id with decl_tag type

[Yonghong Song <yhs@meta.com>]

On 5/29/23 8:17 AM, Eduard Zingerman wrote:
> On Sat, 2023-05-27 at 15:31 -0700, Yonghong Song wrote:
>> Add a selftest where map creation key type_id is a decl_tag
>> pointing to a struct. Without previous patch, a kernel warning will
>> appear similar to the one in the previous patch. With the previous
>> patch, the kernel warning is silenced.
> 
> Looks good to me with a nitpick:
> commit message says "map creation key type_id is a decl_tag",
> but test case uses ".key_type_id = 1" which is INT
> and ".value_type_id = 3" which is DECL_TAG.
> 
> syscall.c:map_check_btf.c applies the same check both for key and value,
> maybe make two tests?

Sounds good. Will fix the commit message and add one more test so both
key and value are covered.

> 
>>
>> Signed-off-by: Yonghong Song <yhs@fb.com>
>> ---
>>   tools/testing/selftests/bpf/prog_tests/btf.c | 20 ++++++++++++++++++++
>>   1 file changed, 20 insertions(+)
>>
>> diff --git a/tools/testing/selftests/bpf/prog_tests/btf.c b/tools/testing/selftests/bpf/prog_tests/btf.c
>> index 210d643fda6c..69521e1dc330 100644
>> --- a/tools/testing/selftests/bpf/prog_tests/btf.c
>> +++ b/tools/testing/selftests/bpf/prog_tests/btf.c
>> @@ -3990,6 +3990,26 @@ static struct btf_raw_test raw_tests[] = {
>>   	.btf_load_err = true,
>>   	.err_str = "Invalid arg#1",
>>   },
>> +{
>> +	.descr = "decl_tag test #18, struct member, decl_tag as the value type",
>> +	.raw_types = {
>> +		BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4),	/* [1] */
>> +		BTF_STRUCT_ENC(0, 2, 8),			/* [2] */
>> +		BTF_MEMBER_ENC(NAME_TBD, 1, 0),
>> +		BTF_MEMBER_ENC(NAME_TBD, 1, 32),
>> +		BTF_DECL_TAG_ENC(NAME_TBD, 2, -1),		/* [3] */
>> +		BTF_END_RAW,
>> +	},
>> +	BTF_STR_SEC("\0m1\0m2\0tag"),
>> +	.map_type = BPF_MAP_TYPE_ARRAY,
>> +	.map_name = "tag_type_check_btf",
>> +	.key_size = sizeof(int),
>> +	.value_size = 8,
>> +	.key_type_id = 1,
>> +	.value_type_id = 3,
>> +	.max_entries = 1,
>> +	.map_create_err = true,
>> +},
>>   {
>>   	.descr = "type_tag test #1",
>>   	.raw_types = {
>