t_kinst_tramp
tramp = curthread->t_kinst_tramp;
td->t_kinst_tramp = kinst_trampoline_alloc(M_WAITOK);
tramp = td->t_kinst_tramp;
td->t_kinst_tramp = NULL;
if (td->t_kinst_tramp != NULL)
td->t_kinst_tramp = tramp;
kinst_trampoline_dealloc_locked(td->t_kinst_tramp,
td->t_kinst_tramp = NULL;