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

[Yonghong Song <yhs@xxxxxxxx>]

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@xxxxxx>
> > ---
> >   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 = {