From cacd6729c09236245d921464eb28e69a6d573412 Mon Sep 17 00:00:00 2001 From: Alan Maguire Date: Fri, 17 Apr 2026 15:30:19 +0100 Subject: libbpf: Adjust btf_vlen() to return a __u32 Now that vlen is 24 bits, btf_vlen() must return a __u32. Adjust use cases in libbpf accordingly. Also add error handling to avoid vlen overflow in btf_type_inc_vlen(). Signed-off-by: Alan Maguire Acked-by: Mykyta Yatsenko Link: https://lore.kernel.org/r/20260417143023.1551481-3-alan.maguire@oracle.com Signed-off-by: Alexei Starovoitov --- tools/lib/bpf/btf.c | 50 ++++++++++++++++++++++++++++++++------------------ 1 file changed, 32 insertions(+), 18 deletions(-) (limited to 'tools/lib/bpf/btf.c') diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c index ceb57b46a878..267904939098 100644 --- a/tools/lib/bpf/btf.c +++ b/tools/lib/bpf/btf.c @@ -421,7 +421,7 @@ static int btf_type_size_unknown(const struct btf *btf, const struct btf_type *t { __u32 l_cnt = btf->hdr.layout_len / sizeof(struct btf_layout); struct btf_layout *l = btf->layout; - __u16 vlen = btf_vlen(t); + __u32 vlen = btf_vlen(t); __u32 kind = btf_kind(t); /* Fall back to base BTF if needed as they share layout information */ @@ -454,7 +454,7 @@ static int btf_type_size_unknown(const struct btf *btf, const struct btf_type *t static int btf_type_size(const struct btf *btf, const struct btf_type *t) { const int base_size = sizeof(struct btf_type); - __u16 vlen = btf_vlen(t); + __u32 vlen = btf_vlen(t); switch (btf_kind(t)) { case BTF_KIND_FWD: @@ -506,7 +506,7 @@ static int btf_bswap_type_rest(struct btf_type *t) struct btf_array *a; struct btf_param *p; struct btf_enum *e; - __u16 vlen = btf_vlen(t); + __u32 vlen = btf_vlen(t); int i; switch (btf_kind(t)) { @@ -1007,7 +1007,7 @@ int btf__align_of(const struct btf *btf, __u32 id) case BTF_KIND_STRUCT: case BTF_KIND_UNION: { const struct btf_member *m = btf_members(t); - __u16 vlen = btf_vlen(t); + __u32 vlen = btf_vlen(t); int i, max_align = 1, align; for (i = 0; i < vlen; i++, m++) { @@ -2121,9 +2121,12 @@ static void *btf_add_type_mem(struct btf *btf, size_t add_sz) btf->hdr.type_len, UINT_MAX, add_sz); } -static void btf_type_inc_vlen(struct btf_type *t) +static int btf_type_inc_vlen(struct btf_type *t) { + if (btf_vlen(t) == BTF_MAX_VLEN) + return -ENOSPC; t->info = btf_type_info(btf_kind(t), btf_vlen(t) + 1, btf_kflag(t)); + return 0; } static void btf_hdr_update_type_len(struct btf *btf, int new_len) @@ -2652,6 +2655,8 @@ int btf__add_field(struct btf *btf, const char *name, int type_id, t = btf_last_type(btf); if (!btf_is_composite(t)) return libbpf_err(-EINVAL); + if (btf_vlen(t) == BTF_MAX_VLEN) + return libbpf_err(-ENOSPC); if (validate_type_id(type_id)) return libbpf_err(-EINVAL); @@ -2686,6 +2691,7 @@ int btf__add_field(struct btf *btf, const char *name, int type_id, /* btf_add_type_mem can invalidate t pointer */ t = btf_last_type(btf); + /* update parent type's vlen and kflag */ t->info = btf_type_info(btf_kind(t), btf_vlen(t) + 1, is_bitfield || btf_kflag(t)); @@ -2796,7 +2802,9 @@ int btf__add_enum_value(struct btf *btf, const char *name, __s64 value) /* update parent type's vlen */ t = btf_last_type(btf); - btf_type_inc_vlen(t); + err = btf_type_inc_vlen(t); + if (err) + return libbpf_err(err); /* if negative value, set signedness to signed */ if (value < 0) @@ -2873,7 +2881,9 @@ int btf__add_enum64_value(struct btf *btf, const char *name, __u64 value) /* update parent type's vlen */ t = btf_last_type(btf); - btf_type_inc_vlen(t); + err = btf_type_inc_vlen(t); + if (err) + return libbpf_err(err); btf_hdr_update_type_len(btf, btf->hdr.type_len + sz); return 0; @@ -3115,7 +3125,9 @@ int btf__add_func_param(struct btf *btf, const char *name, int type_id) /* update parent type's vlen */ t = btf_last_type(btf); - btf_type_inc_vlen(t); + err = btf_type_inc_vlen(t); + if (err) + return libbpf_err(err); btf_hdr_update_type_len(btf, btf->hdr.type_len + sz); return 0; @@ -3257,7 +3269,9 @@ int btf__add_datasec_var_info(struct btf *btf, int var_type_id, __u32 offset, __ /* update parent type's vlen */ t = btf_last_type(btf); - btf_type_inc_vlen(t); + err = btf_type_inc_vlen(t); + if (err) + return libbpf_err(err); btf_hdr_update_type_len(btf, btf->hdr.type_len + sz); return 0; @@ -4311,7 +4325,7 @@ static long btf_hash_enum(struct btf_type *t) static bool btf_equal_enum_members(struct btf_type *t1, struct btf_type *t2) { const struct btf_enum *m1, *m2; - __u16 vlen; + __u32 vlen; int i; vlen = btf_vlen(t1); @@ -4329,7 +4343,7 @@ static bool btf_equal_enum_members(struct btf_type *t1, struct btf_type *t2) static bool btf_equal_enum64_members(struct btf_type *t1, struct btf_type *t2) { const struct btf_enum64 *m1, *m2; - __u16 vlen; + __u32 vlen; int i; vlen = btf_vlen(t1); @@ -4406,7 +4420,7 @@ static long btf_hash_struct(struct btf_type *t) static bool btf_shallow_equal_struct(struct btf_type *t1, struct btf_type *t2) { const struct btf_member *m1, *m2; - __u16 vlen; + __u32 vlen; int i; if (!btf_equal_common(t1, t2)) @@ -4482,7 +4496,7 @@ static bool btf_compat_array(struct btf_type *t1, struct btf_type *t2) static long btf_hash_fnproto(struct btf_type *t) { const struct btf_param *member = btf_params(t); - __u16 vlen = btf_vlen(t); + __u32 vlen = btf_vlen(t); long h = btf_hash_common(t); int i; @@ -4504,7 +4518,7 @@ static long btf_hash_fnproto(struct btf_type *t) static bool btf_equal_fnproto(struct btf_type *t1, struct btf_type *t2) { const struct btf_param *m1, *m2; - __u16 vlen; + __u32 vlen; int i; if (!btf_equal_common(t1, t2)) @@ -4530,7 +4544,7 @@ static bool btf_equal_fnproto(struct btf_type *t1, struct btf_type *t2) static bool btf_compat_fnproto(struct btf_type *t1, struct btf_type *t2) { const struct btf_param *m1, *m2; - __u16 vlen; + __u32 vlen; int i; /* skip return type ID */ @@ -5077,7 +5091,7 @@ static int btf_dedup_is_equiv(struct btf_dedup *d, __u32 cand_id, case BTF_KIND_STRUCT: case BTF_KIND_UNION: { const struct btf_member *cand_m, *canon_m; - __u16 vlen; + __u32 vlen; if (!btf_shallow_equal_struct(cand_type, canon_type)) return 0; @@ -5105,7 +5119,7 @@ static int btf_dedup_is_equiv(struct btf_dedup *d, __u32 cand_id, case BTF_KIND_FUNC_PROTO: { const struct btf_param *cand_p, *canon_p; - __u16 vlen; + __u32 vlen; if (!btf_compat_fnproto(cand_type, canon_type)) return 0; @@ -5439,7 +5453,7 @@ static int btf_dedup_ref_type(struct btf_dedup *d, __u32 type_id) case BTF_KIND_FUNC_PROTO: { struct btf_param *param; - __u16 vlen; + __u32 vlen; int i; ref_type_id = btf_dedup_ref_type(d, t->type); -- cgit v1.2.3 From 0831b110eb4591e4ad8c5fd0d8f0f3f9979a5ff5 Mon Sep 17 00:00:00 2001 From: Antoine Tenart Date: Fri, 17 Apr 2026 10:33:17 +0200 Subject: libbpf: Fix deduplication of typedef with base definitions When deduplicating definitions for a module, typedef defined in the base are not removed. This is because the hash used for base types differs from the one used in the deduplication logic in btf_dedup_struct_type. This was introduced by the referenced commit when moving the typedef deduplication logic handling from btf_dedup_ref_type to btf_dedup_struct_type, as this also changed the hash logic (btf_hash_common to btf_hash_typedef). This also impacts other types referencing those typedef (e.g. const). In my test, the BTF section size of the openvswitch module went from 31KB to 45KB. Fixes: 3781413465df ("libbpf: Fix BTF dedup to support recursive typedef definitions"). Signed-off-by: Antoine Tenart Signed-off-by: Andrii Nakryiko Tested-by: Alan Maguire Reviewed-by: Alan Maguire Link: https://lore.kernel.org/bpf/20260417083319.32716-1-atenart@kernel.org --- tools/lib/bpf/btf.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'tools/lib/bpf/btf.c') diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c index 267904939098..823bce895178 100644 --- a/tools/lib/bpf/btf.c +++ b/tools/lib/bpf/btf.c @@ -4592,12 +4592,14 @@ static int btf_dedup_prep(struct btf_dedup *d) case BTF_KIND_RESTRICT: case BTF_KIND_PTR: case BTF_KIND_FWD: - case BTF_KIND_TYPEDEF: case BTF_KIND_FUNC: case BTF_KIND_FLOAT: case BTF_KIND_TYPE_TAG: h = btf_hash_common(t); break; + case BTF_KIND_TYPEDEF: + h = btf_hash_typedef(t); + break; case BTF_KIND_INT: case BTF_KIND_DECL_TAG: h = btf_hash_int_decl_tag(t); -- cgit v1.2.3