On Tue, Feb 25, 2025 at 1:30 AM Alexei Starovoitov
<alexei.starovoitov@xxxxxxxxx> wrote:
>
> On Mon, Feb 24, 2025 at 3:46 AM Yafang Shao <laoar.shao@xxxxxxxxx> wrote:
> >
> > + } else if (prog->expected_attach_type == BPF_TRACE_FEXIT &&
> > + btf_id_set_contains(&fexit_deny, btf_id)) {
> > + verbose(env, "Attaching fexit to __noreturn functions is rejected.\n");
> > + return -EINVAL;
>
> Just realized that this needs to include
> prog->expected_attach_type == BPF_MODIFY_RETURN
> since it's doing __bpf_tramp_enter() too.
I will add it.
>
> Also the list must only contain existing functions.
> Otherwise there are plenty of build warns:
> BTFIDS vmlinux
> WARN: resolve_btfids: unresolved symbol xen_start_kernel
> WARN: resolve_btfids: unresolved symbol xen_cpu_bringup_again
> WARN: resolve_btfids: unresolved symbol usercopy_abort
> WARN: resolve_btfids: unresolved symbol snp_abort
> WARN: resolve_btfids: unresolved symbol sev_es_terminate
> WARN: resolve_btfids: unresolved symbol rust_helper_BUG
> ...
I missed these warnings.
It looks like we need to add "#ifdef XXXX" to each function.
Alternatively, could we just compare the function name with
prog->aux->attach_func_name instead?
--
Regards
Yafang
