when haproxy will invoke hijacker(final)

Hello:

       Sorry to send an uncompleted mail before.
       Now I am adding an extra function to haproxy, but when I debug, I find at expiration, haproxy  core dump on invoking hijacker. But I could not find when the buffer->flags ORING BF_HIJACKER, I am really confused. 
       and in 1.4.2 version hijacker are always null? how can I set this function? could I remove all the code in session.c
      process_session() 
============
       if (unlikely(s->rep->flags & BF_HIJACK)) {
		/* In inject mode, we wake up everytime something has
		 * happened on the write side of the buffer.
		 */
		unsigned int flags = s->rep->flags;

		if ((s->rep->flags & (BF_WRITE_PARTIAL|BF_WRITE_ERROR|BF_SHUTW)) &&
		    !(s->rep->flags & BF_FULL)) {
			s->rep->hijacker(s, s->rep);


		}


		if ((s->rep->flags ^ flags) & BF_MASK_STATIC) {
			rpf_last = s->rep->flags;
			goto resync_response;


		}

	}
=====================  
     Thanks!     


Mr. XiaoxinLin               xiaoxin#staff.sina.com.cn