btf_dump_type_data_check_zero() uses -ENODATA to indicate that a value is zero. The array path handles this sentinel correctly, but the struct and union path compares the return value against positive ENODATA.
As a result, the member loop returns after examining its first member. A nested struct or union whose first member is zero can therefore be treated as entirely zero even when a later member is non-zero. Compare against -ENODATA so zero members are skipped while looking for a non-zero member. Signed-off-by: Luis Vieira <[email protected]> --- tools/lib/bpf/btf_dump.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/lib/bpf/btf_dump.c b/tools/lib/bpf/btf_dump.c index 996e61b5f11f..ad43bbd3b442 100644 --- a/tools/lib/bpf/btf_dump.c +++ b/tools/lib/bpf/btf_dump.c @@ -2564,7 +2564,7 @@ static int btf_dump_type_data_check_zero(struct btf_dump *d, bit_sz = btf_member_bitfield_size(t, i); err = btf_dump_type_data_check_zero(d, mtype, m->type, data + moffset / 8, moffset % 8, bit_sz); - if (err != ENODATA) + if (err != -ENODATA) return err; } return -ENODATA; -- 2.43.0
