[PATCH bpf v2 2/2] selftests/bpf: ensure typedef are deduplicated in split BTF

Antoine Tenart
2026-04-17T08:33:30Z

If a typedef is defined both in a base and in a split BTF, after
deduplication a single instance should be found in the base BTF.

Suggested-by: Alan Maguire <alan.maguire@oracle.com>
Signed-off-by: Antoine Tenart <atenart@kernel.org>
---

Since v1:
- Added this patch.

.../bpf/prog_tests/btf_dedup_split.c | 48 ++++++++++++-------
1 file changed, 32 insertions(+), 16 deletions(-)

diff --git a/tools/testing/selftests/bpf/prog_tests/btf_dedup_split.c b/tools/testing/selftests/bpf/prog_tests/btf_dedup_split.c
index 5bc15bb6b7ce..0db7707ae90d 100644
--- a/tools/testing/selftests/bpf/prog_tests/btf_dedup_split.c
+++ b/tools/testing/selftests/bpf/prog_tests/btf_dedup_split.c
@@ -20,18 +20,22 @@ static void test_split_simple() {
btf__add_struct(btf1, "s1", 4); /* [3] struct s1 { */
btf__add_field(btf1, "f1", 1, 0, 0); /* int f1; */
/* } */
+ btf__add_typedef(btf1, "t1", 1); /* [4] typedef int */

VALIDATE_RAW_BTF(
btf1,
"[1] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED",
"[2] PTR '(anon)' type_id=1",
"[3] STRUCT 's1' size=4 vlen=1\n"
- "\t'f1' type_id=1 bits_offset=0");
+ "\t'f1' type_id=1 bits_offset=0",
+ "[4] TYPEDEF 't1' type_id=1");

ASSERT_STREQ(btf_type_c_dump(btf1), "\
struct s1 {\n\
int f1;\n\
-};\n\n", "c_dump");
+};\n\
+\n\
+typedef int t1;\n\n", "c_dump");

btf2 = btf__new_empty_split(btf1);
if (!ASSERT_OK_PTR(btf2, "empty_split_btf"))
@@ -49,39 +53,46 @@ struct s1 {\n\
ASSERT_EQ(btf_is_int(t), true, "int_kind");
ASSERT_STREQ(btf__str_by_offset(btf2, t->name_off), "int", "int_name");

- btf__add_struct(btf2, "s2", 16); /* [4] struct s2 { */
- btf__add_field(btf2, "f1", 6, 0, 0); /* struct s1 f1; */
- btf__add_field(btf2, "f2", 5, 32, 0); /* int f2; */
+ btf__add_struct(btf2, "s2", 16); /* [5] struct s2 { */
+ btf__add_field(btf2, "f1", 7, 0, 0); /* struct s1 f1; */
+ btf__add_field(btf2, "f2", 6, 32, 0); /* int f2; */
btf__add_field(btf2, "f3", 2, 64, 0); /* int *f3; */
/* } */

/* duplicated int */
- btf__add_int(btf2, "int", 4, BTF_INT_SIGNED); /* [5] int */
+ btf__add_int(btf2, "int", 4, BTF_INT_SIGNED); /* [6] int */

/* duplicated struct s1 */
- btf__add_struct(btf2, "s1", 4); /* [6] struct s1 { */
- btf__add_field(btf2, "f1", 5, 0, 0); /* int f1; */
+ btf__add_struct(btf2, "s1", 4); /* [7] struct s1 { */
+ btf__add_field(btf2, "f1", 6, 0, 0); /* int f1; */
/* } */

+ /* duplicated typedef t1 */
+ btf__add_typedef(btf2, "t1", 6); /* [8] typedef int */
+
VALIDATE_RAW_BTF(
btf2,
"[1] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED",
"[2] PTR '(anon)' type_id=1",
"[3] STRUCT 's1' size=4 vlen=1\n"
"\t'f1' type_id=1 bits_offset=0",
- "[4] STRUCT 's2' size=16 vlen=3\n"
- "\t'f1' type_id=6 bits_offset=0\n"
- "\t'f2' type_id=5 bits_offset=32\n"
+ "[4] TYPEDEF 't1' type_id=1",
+ "[5] STRUCT 's2' size=16 vlen=3\n"
+ "\t'f1' type_id=7 bits_offset=0\n"
+ "\t'f2' type_id=6 bits_offset=32\n"
"\t'f3' type_id=2 bits_offset=64",
- "[5] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED",
- "[6] STRUCT 's1' size=4 vlen=1\n"
- "\t'f1' type_id=5 bits_offset=0");
+ "[6] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED",
+ "[7] STRUCT 's1' size=4 vlen=1\n"
+ "\t'f1' type_id=6 bits_offset=0",
+ "[8] TYPEDEF 't1' type_id=6");

ASSERT_STREQ(btf_type_c_dump(btf2), "\
struct s1 {\n\
int f1;\n\
};\n\
\n\
+typedef int t1;\n\
+\n\
struct s1___2 {\n\
int f1;\n\
};\n\
@@ -90,7 +101,9 @@ struct s2 {\n\
struct s1___2 f1;\n\
int f2;\n\
int *f3;\n\
-};\n\n", "c_dump");
+};\n\
+\n\
+typedef int t1___2;\n\n", "c_dump");

err = btf__dedup(btf2, NULL);
if (!ASSERT_OK(err, "btf_dedup"))
@@ -102,7 +115,8 @@ struct s2 {\n\
"[2] PTR '(anon)' type_id=1",
"[3] STRUCT 's1' size=4 vlen=1\n"
"\t'f1' type_id=1 bits_offset=0",
- "[4] STRUCT 's2' size=16 vlen=3\n"
+ "[4] TYPEDEF 't1' type_id=1",
+ "[5] STRUCT 's2' size=16 vlen=3\n"
"\t'f1' type_id=3 bits_offset=0\n"
"\t'f2' type_id=1 bits_offset=32\n"
"\t'f3' type_id=2 bits_offset=64");
@@ -112,6 +126,8 @@ struct s1 {\n\
int f1;\n\
};\n\
\n\
+typedef int t1;\n\
+\n\
struct s2 {\n\
struct s1 f1;\n\
int f2;\n\
--
2.53.0