5.1.12:
-------

[sbester@fc4 sqlthreads]$ ./sqlthreads 30 60 1 0 "drop table if exists t1;create table t1 (i int);lock tables t1 read;show open tables;unlock tables;" 127.0.0.1 3306 test root
Testing DB connection before spawning threads....
Connecting....
Connected....
Thread Safe is ON
Spawning 30 new threads
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 
Database connections are setup! Check above for errors.
Completed spawning new threads from the application!
Now running for 60 seconds (until 1153582485)
Query failed (2013) - Lost connection to MySQL server during query: drop table if exists t1;create table t1 (i int);lock tables t1 read;show open tables;unlock tables;



Version: '5.1.12-beta-debug'  socket: '/tmp/my.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=8388572
read_buffer_size=131072
max_used_connections=30
max_connections=100
threads_connected=30
It is possible that mysqld could use up to 
key_buffer_size + (read_buffer_size + sort_buffer_size)*max_connections = 225788 K
bytes of memory
Hope that's ok; if not, decrease some variables in the equation.

thd=0xa018ad8
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=0xb7432b5c, backtrace may not be correct.
Stack range sanity check OK, backtrace follows:
0x81887ab handle_segfault + 461
0x18c420 (?)
0xa0256a8 _end + 27957816
0x8286fbb _Z24get_schema_tables_resultP4JOIN + 367
0x81f934a _ZN4JOIN4execEv + 1858
0x81fb909 _Z12mysql_selectP3THDPPP4ItemP13st_table_listjR4ListIS1_ES2_jP8st_orderSB_S2_SB_mP13select_resultP18st_select_lex_unitP13st_sel + 1551
0x81fbdf3 _Z13handle_selectP3THDP6st_lexP13select_resultm + 429
0x819fa8a _Z21execute_sqlcom_selectP3THDP13st_table_list + 712
0x81a01c9 _Z21mysql_execute_commandP3THD + 1313
0x81a81c4 _Z11mysql_parseP3THDPcj + 376
0x81a8cb1 _Z16dispatch_command19enum_server_commandP3THDPcj + 2451
0x81a9e60 _Z10do_commandP3THD + 516
0x81aaa47 handle_one_connection + 2871
0x880b80 (?)
0x597dee (?)

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 0xa024b14 = show open tables;unlock tables
thd->thread_id=19
The manual page at http://www.mysql.com/doc/en/Crashing.html contains
information that should help you find out what is causing the crash.