Commit 556a3994 authored by Pu Lehui's avatar Pu Lehui Committed by Andrii Nakryiko
Browse files

selftests/bpf: Add distilled BTF test about marking BTF_IS_EMBEDDED 



When redirecting the split BTF to the vmlinux base BTF, we need to mark
the distilled base struct/union members of split BTF structs/unions in
id_map with BTF_IS_EMBEDDED. This indicates that these types must match
both name and size later. So if a needed composite type, which is the
member of composite type in the split BTF, has a different size in the
base BTF we wish to relocate with, btf__relocate() should error out.

Signed-off-by: default avatarPu Lehui <pulehui@huawei.com>
Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20250115100241.4171581-4-pulehui@huaweicloud.com
parent 5ca681a8

tools/testing/selftests/bpf/prog_tests/btf_distill.c

+72 −0
Original line number Diff line number Diff line
@@ -601,6 +601,76 @@ static void test_distilled_endianness(void) 
	btf__free(base);

}



/* If a needed composite type, which is the member of composite type

 * in the split BTF, has a different size in the base BTF we wish to

 * relocate with, btf__relocate() should error out.

 */

static void test_distilled_base_embedded_err(void)

{

	struct btf *btf1 = NULL, *btf2 = NULL, *btf3 = NULL, *btf4 = NULL, *btf5 = NULL;



	btf1 = btf__new_empty();

	if (!ASSERT_OK_PTR(btf1, "empty_main_btf"))

		return;



	btf__add_int(btf1, "int", 4, BTF_INT_SIGNED);   /* [1] int */

	btf__add_struct(btf1, "s1", 4);                 /* [2] struct s1 { */

	btf__add_field(btf1, "f1", 1, 0, 0);            /*      int f1; */

							/* } */

	VALIDATE_RAW_BTF(

		btf1,

		"[1] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED",

		"[2] STRUCT 's1' size=4 vlen=1\n"

		"\t'f1' type_id=1 bits_offset=0");



	btf2 = btf__new_empty_split(btf1);

	if (!ASSERT_OK_PTR(btf2, "empty_split_btf"))

		goto cleanup;



	btf__add_struct(btf2, "with_embedded", 8);      /* [3] struct with_embedded { */

	btf__add_field(btf2, "e1", 2, 0, 0);		/*      struct s1 e1; */

							/* } */



	VALIDATE_RAW_BTF(

		btf2,

		"[1] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED",

		"[2] STRUCT 's1' size=4 vlen=1\n"

		"\t'f1' type_id=1 bits_offset=0",

		"[3] STRUCT 'with_embedded' size=8 vlen=1\n"

		"\t'e1' type_id=2 bits_offset=0");



	if (!ASSERT_EQ(0, btf__distill_base(btf2, &btf3, &btf4),

		       "distilled_base") ||

	    !ASSERT_OK_PTR(btf3, "distilled_base") ||

	    !ASSERT_OK_PTR(btf4, "distilled_split") ||

	    !ASSERT_EQ(2, btf__type_cnt(btf3), "distilled_base_type_cnt"))

		goto cleanup;



	VALIDATE_RAW_BTF(

		btf4,

		"[1] STRUCT 's1' size=4 vlen=0",

		"[2] STRUCT 'with_embedded' size=8 vlen=1\n"

		"\t'e1' type_id=1 bits_offset=0");



	btf5 = btf__new_empty();

	if (!ASSERT_OK_PTR(btf5, "empty_reloc_btf"))

		goto cleanup;



	btf__add_int(btf5, "int", 4, BTF_INT_SIGNED);   /* [1] int */

	/* struct with the same name but different size */

	btf__add_struct(btf5, "s1", 8);                 /* [2] struct s1 { */

	btf__add_field(btf5, "f1", 1, 0, 0);            /*      int f1; */

							/* } */



	ASSERT_EQ(btf__relocate(btf4, btf5), -EINVAL, "relocate_split");

cleanup:

	btf__free(btf5);

	btf__free(btf4);

	btf__free(btf3);

	btf__free(btf2);

	btf__free(btf1);

}



void test_btf_distill(void)

{

	if (test__start_subtest("distilled_base"))
@@ -613,6 +683,8 @@ void test_btf_distill(void) 
		test_distilled_base_multi_err();

	if (test__start_subtest("distilled_base_multi_err2"))

		test_distilled_base_multi_err2();

	if (test__start_subtest("distilled_base_embedded_err"))

		test_distilled_base_embedded_err();

	if (test__start_subtest("distilled_base_vmlinux"))

		test_distilled_base_vmlinux();

	if (test__start_subtest("distilled_endianness"))