On Tue, Aug 04, 2020 at 11:24:07AM -0700, Andrii Nakryiko wrote: > + > +SEC("raw_tracepoint/sys_enter") > +int test_core_type_id(void *ctx) > +{ > + struct core_reloc_type_id_output *out = (void *)&data.out; > + > + out->local_anon_struct = bpf_core_type_id_local(struct { int marker_field; }); > + out->local_anon_union = bpf_core_type_id_local(union { int marker_field; }); > + out->local_anon_enum = bpf_core_type_id_local(enum { MARKER_ENUM_VAL = 123 }); > + out->local_anon_func_proto_ptr = bpf_core_type_id_local(_Bool(*)(int)); > + out->local_anon_void_ptr = bpf_core_type_id_local(void *); > + out->local_anon_arr = bpf_core_type_id_local(_Bool[47]); > + > + out->local_struct = bpf_core_type_id_local(struct a_struct); > + out->local_union = bpf_core_type_id_local(union a_union); > + out->local_enum = bpf_core_type_id_local(enum an_enum); > + out->local_int = bpf_core_type_id_local(int); > + out->local_struct_typedef = bpf_core_type_id_local(named_struct_typedef); > + out->local_func_proto_typedef = bpf_core_type_id_local(func_proto_typedef); > + out->local_arr_typedef = bpf_core_type_id_local(arr_typedef); > + > + out->targ_struct = bpf_core_type_id_kernel(struct a_struct); > + out->targ_union = bpf_core_type_id_kernel(union a_union); > + out->targ_enum = bpf_core_type_id_kernel(enum an_enum); > + out->targ_int = bpf_core_type_id_kernel(int); > + out->targ_struct_typedef = bpf_core_type_id_kernel(named_struct_typedef); > + out->targ_func_proto_typedef = bpf_core_type_id_kernel(func_proto_typedef); > + out->targ_arr_typedef = bpf_core_type_id_kernel(arr_typedef); bpf_core_type_id_kernel() returns btf_id of the type in vmlinux BTF or zero, so what is the point of above tests? All targ_* will be zero. Should the test find a type that actually exists in the kernel? What am I missing?