On Wed, Jan 7, 2026 at 6:25 PM Menglong Dong [off-list ref] wrote:

+       } else if (func_id == special_kfunc_list[KF_bpf_session_is_return]) {
+               if (prog->expected_attach_type == BPF_TRACE_FSESSION)
+                       addr = (unsigned long)bpf_fsession_is_return;

...

+bool bpf_fsession_is_return(void *ctx)
+{
+       /* This helper call is inlined by verifier. */
+       return !!(((u64 *)ctx)[-1] & (1 << BPF_TRAMP_M_IS_RETURN));
+}
+

Why do this specialization and introduce a global function
that will never be called, since it will be inlined anyway?

Remove the first hunk and make the 2nd a comment instead of a real function?