TB_TO_BE_FREED
ASSERT(state != TB_TO_BE_FREED);
mtb->mtb_state = TB_TO_BE_FREED;
ASSERT(state != TB_TO_BE_FREED);
mtb->mtb_state = TB_TO_BE_FREED;
ASSERT(mtb->mtb_state != TB_TO_BE_FREED);
if (state == TB_TO_BE_FREED) {