i found rather serious false assumption in sys/kern/uipc_mbuf.c:m_dup(). i would like to disable the function for safety (wrap by #if 0). are there anyone using the function? the false assumption: if a mbuf has M_EXT bit raised, m_ext.ext_siz == MCLBYTES (cluster memory region allocated via MCLGET). the assumption does not hold itojun