While trying to reproduce the bug:1737 with 3.0.3rc1 , core file details :

(gdb) f 0
#0  0x00002b7ca8727d94 in server_lookup (frame=0x22eee08, bound_xl=0x1cb8130, hdr=0x229ba50, hdrlen=169, iobuf=0x0) at server-protocol.c:2661
2661	in server-protocol.c
(gdb) p *state
Cannot access memory at address 0x0
(gdb) p state
$1 = (server_state_t *) 0x0
(gdb) bt
#0  0x00002b7ca8727d94 in server_lookup (frame=0x22eee08, bound_xl=0x1cb8130, hdr=0x229ba50, hdrlen=169, iobuf=0x0) at server-protocol.c:2661
#1  0x00002b7ca8733ec7 in protocol_server_interpret (this=0x1cb8a20, trans=0x2aaaac589bb0, hdr_p=0x229ba50 "", hdrlen=169, iobuf=0x0) at server-protocol.c:6323
#2  0x00002b7ca8735067 in protocol_server_pollin (this=0x1cb8a20, trans=0x2aaaac589bb0) at server-protocol.c:6726
#3  0x00002b7ca8735276 in notify (this=0x1cb8a20, event=2, data=0x2aaaac589bb0) at server-protocol.c:6782
#4  0x00002b7ca760c75a in xlator_notify (xl=0x1cb8a20, event=2, data=0x2aaaac589bb0) at xlator.c:924
#5  0x00002aaaaaaaee96 in socket_event_poll_in (this=0x2aaaac589bb0) at socket.c:731
#6  0x00002aaaaaaaf18b in socket_event_handler (fd=10, idx=2, data=0x2aaaac589bb0, poll_in=1, poll_out=0, poll_err=0) at socket.c:831
#7  0x00002b7ca7631705 in event_dispatch_epoll_handler (event_pool=0x1cb26e0, events=0x1cc0f30, i=0) at event.c:804
#8  0x00002b7ca76318da in event_dispatch_epoll (event_pool=0x1cb26e0) at event.c:867
#9  0x00002b7ca7631bf0 in event_dispatch (event_pool=0x1cb26e0) at event.c:975
#10 0x0000000000405f2b in main (argc=8, argv=0x7fff90b7c9b8) at glusterfsd.c:1413