Version: '5.1.17-beta-debug'  socket: '/tmp/mysql.sock'  port: 3306  yes
mysqld got signal 11;
This could be because you hit a bug. It is also possible that this binary
or one of the libraries it was linked against is corrupt, improperly built,
or misconfigured. This error can also be caused by malfunctioning hardware.
We will try our best to scrape up some info that will hopefully help diagnose
the problem, but since we have already crashed, something is definitely wrong
and this may fail.

key_buffer_size=8388600
read_buffer_size=131072
max_used_connections=1
max_threads=151
threads_connected=1
It is possible that mysqld could use up to 
key_buffer_size + (read_buffer_size + sort_buffer_size)*max_threads = 337597 K
bytes of memory
Hope that's ok; if not, decrease some variables in the equation.

thd: 0x8dc46b8
Attempting backtrace. You can use the following information to find out
where mysqld died. If you see no messages after this, something went
terribly wrong...
Cannot determine thread, fp=0x4286427c, backtrace may not be correct.
Stack range sanity check OK, backtrace follows:
0x81f4d31 handle_segfault + 689
0x812e33d _ZN10Item_field15fix_outer_fieldEP3THDPP5FieldPP4Item + 157
0x8131563 _ZN10Item_field10fix_fieldsEP3THDPP4Item + 1267
0x825a47d _Z18find_order_in_listP3THDPP4ItemP13st_table_listP8st_orderR4ListIS1_ESA_b + 749
0x8276f33 _ZN4JOIN7prepareEPPP4ItemP13st_table_listjS1_jP8st_orderS7_S1_S7_P13st_select_lexP18st_select_lex_unit + 979
0x827809a _Z12mysql_selectP3THDPPP4ItemP13st_table_listjR4ListIS1_ES2_jP8st_orderSB_S2_SB_yP13select_resultP18st_select_lex_unitP13st_sel + 2010
0x837e3f8 _ZN18st_select_lex_unit4execEv + 3128
0x83804fe _Z21mysql_derived_fillingP3THDP6st_lexP13st_table_list + 638
0x8380224 _Z20mysql_handle_derivedP6st_lexPFbP3THDS0_P13st_table_listE + 84
0x8249ea5 _Z20open_and_lock_tablesP3THDP13st_table_list + 645
0x8202e31 _Z21execute_sqlcom_selectP3THDP13st_table_list + 97
0x8209b81 _Z21mysql_execute_commandP3THD + 23697
0x820e8b8 _Z11mysql_parseP3THDPcj + 872
0x820fb09 _Z16dispatch_command19enum_server_commandP3THDPcj + 4553
0x821080e _Z10do_commandP3THD + 430
0x81fc2cf handle_one_connection + 271
0x4004daa7 _end + 931859575
0x4017ec2e _end + 933109246
New value of fp=(nil) failed sanity check, terminating stack trace!
Please read http://dev.mysql.com/doc/mysql/en/using-stack-trace.html and follow instructions on how to resolve the stack trace. Resolved
stack trace is much more helpful in diagnosing the problem, so please do 
resolve it
Trying to get some variables.
Some pointers may be invalid and cause the dump to abort...
thd->query at 0x8dce4e0 = SELECT User FROM
(
        SELECT * FROM mysql.user
UNION
        SELECT * FROM mysql.user
ORDER BY unknown_column
) AS test
thd->thread_id=1