BTF_KIND_ENUM stores enumerators in a signed 32-bit field even for unsigned enums. btf_dump_enum_data() compares unsigned data against that signed field, so values with bit 31 set fail to match their names. get_map_field_long() also sign-extends the field: for example, __ulong(map_extra, 0x80000000) becomes 0xffffffff80000000 instead of the requested arena mapping address. Add btf_enum_value() to extend an enumerator according to kflag and use it for data-name matching and enum-backed map fields. Return __u64, consistent with btf_enum64_value(), while sign-extending signed values. Fixes: d90ec262b35b ("libbpf: Add enum64 support for btf_dump") Fixes: d147357e2e59 ("libbpf: Allow specifying 64-bit integers in map BTF.") Suggested-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/DMJG1R2YIJRK.16CZLV9S5U7Z7@gmail.com/ Signed-off-by: Hungyu Lin --- Changes in v4: - Return __u64 from the shared helper and compare normalized values. - Drop the legacy comparison and rely on kflag, as requested by Andrii. tools/lib/bpf/btf.h | 6 ++++++ tools/lib/bpf/btf_dump.c | 2 +- tools/lib/bpf/libbpf.c | 2 +- 3 files changed, 8 insertions(+), 2 deletions(-) diff --git a/tools/lib/bpf/btf.h b/tools/lib/bpf/btf.h index 57f12630c5d1..d74c92056f0f 100644 --- a/tools/lib/bpf/btf.h +++ b/tools/lib/bpf/btf.h @@ -636,6 +636,12 @@ static inline struct btf_enum *btf_enum(const struct btf_type *t) return (struct btf_enum *)(t + 1); } +/* btf_enum->val is signed even for unsigned enums; kflag records the sign. */ +static inline __u64 btf_enum_value(const struct btf_type *t, const struct btf_enum *e) +{ + return btf_kflag(t) ? (__s64)e->val : (__u32)e->val; +} + struct btf_enum64; static inline struct btf_enum64 *btf_enum64(const struct btf_type *t) diff --git a/tools/lib/bpf/btf_dump.c b/tools/lib/bpf/btf_dump.c index fcd97aa90589..602664a6adef 100644 --- a/tools/lib/bpf/btf_dump.c +++ b/tools/lib/bpf/btf_dump.c @@ -2378,7 +2378,7 @@ static int btf_dump_enum_data(struct btf_dump *d, const struct btf_enum *e; for (i = 0, e = btf_enum(t); i < btf_vlen(t); i++, e++) { - if (value != e->val) + if ((__u64)value != btf_enum_value(t, e)) continue; btf_dump_type_values(d, "%s", btf_name_of(d, e->name_off)); return 0; diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 0e2a93a42908..44134421bd7d 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -2650,7 +2650,7 @@ static bool get_map_field_long(const char *map_name, const struct btf *btf, if (btf_is_enum(t)) { const struct btf_enum *e = btf_enum(t); - *res = e->val; + *res = btf_enum_value(t, e); } else { const struct btf_enum64 *e = btf_enum64(t); -- 2.43.0