check_refcount
void check_refcount(struct node *lhs, struct node *rhs, void *arg);
lut_walk(Faults, (lut_cb)check_refcount, (void *)T_FAULT);
lut_walk(Upsets, (lut_cb)check_refcount, (void *)T_UPSET);
lut_walk(Errors, (lut_cb)check_refcount, (void *)T_ERROR);
lut_walk(Ereports, (lut_cb)check_refcount, (void *)T_EREPORT);
lut_walk(SERDs, (lut_cb)check_refcount, (void *)T_SERD);