Comment 7 for bug 1266980

Clearly repeatable with recent PS 5.1 from bzr:

openxs@ao756:~/dbs/p5.1/mysql-test$ ./mtr --record 1266980
Logging: ./mtr --record 1266980
140108 12:13:42 [Note] Plugin 'FEDERATED' is disabled.
MySQL Version 5.1.73
Checking supported features...
 - skipping ndbcluster
 - SSL connections supported
Collecting tests...
vardir: /home/openxs/dbs/p5.1/mysql-test/var
Checking leftover processes...
Removing old var directory...
Creating var directory '/home/openxs/dbs/p5.1/mysql-test/var'...
Installing system database...
Using server port 40374

==============================================================================

TEST RESULT TIME (ms)
------------------------------------------------------------

worker[1] Using MTR_BUILD_THREAD 300, with reserved ports 13000..13009
main.1266980 [ fail ]
        Test ended at 2014-01-08 12:13:45

CURRENT_TEST: main.1266980
mysqltest: At line 4: query 'SELECT GROUP_CONCAT('\\\\\n* ', '\'',user,'\'@\'',host,'\'' ORDER BY user, host) AS user_spec FROM mysql.user' failed: 2013: Lost connection to MySQL server during query

The result from queries just before the failure was:
SELECT GROUP_CONCAT('\\\\\n* ', '\'',user,'\'@\'',host,'\'' ORDER BY user, host, .) AS user_spec FROM mysql.user;
ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ') AS user_spec FROM mysql.user' at line 1

Server [mysqld.1 - pid: 27812, winpid: 27812, exit: 256] failed during test run
Server log from this test:
----------SERVER LOG START-----------
140108 13:13:44 [Warning] '--default-character-set' is deprecated and will be removed in a future release. Please use '--character-set-server' instead.
140108 13:13:44 [Note] Plugin 'FEDERATED' is disabled.
140108 13:13:44 [Note] Plugin 'InnoDB' is disabled.
140108 13:13:44 [Warning] /home/openxs/dbs/p5.1/libexec/mysqld: unknown variable 'loose-debug-sync-timeout=300'
140108 13:13:45 [Note] Event Scheduler: Loaded 0 events
140108 13:13:45 [Note] /home/openxs/dbs/p5.1/libexec/mysqld: ready for connections.
Version: '5.1.73-log' socket: '/home/openxs/dbs/p5.1/mysql-test/var/tmp/mysqld.1.sock' port: 13000 Source distribution
10:13:45 UTC - 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.
Please help us make Percona Server better by reporting any
bugs at http://bugs.percona.com/

key_buffer_size=1048576
read_buffer_size=131072
max_used_connections=1
max_threads=151
thread_count=1
connection_count=1
It is possible that mysqld could use up to
key_buffer_size + (read_buffer_size + sort_buffer_size)*max_threads = 60685 K bytes of memory
Hope that's ok; if not, decrease some variables in the equation.

Thread pointer: 0x1be6c70
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...
stack_bottom = 7fdbde9fde68 thread_stack 0x40000
/home/openxs/dbs/p5.1/libexec/mysqld(my_print_stacktrace+0x26) [0x886f26]
/home/openxs/dbs/p5.1/libexec/mysqld(handle_fatal_signal+0x356) [0x6a5656]
/lib/x86_64-linux-gnu/libpthread.so.0(+0xfbd0) [0x7fdbde732bd0]
/home/openxs/dbs/p5.1/libexec/mysqld(Item_func_group_concat::Item_func_group_concat(Name_resolution_context*, bool, List<Item>*, SQL_I_List<st_order> const&, String*)+0x1f3) [0x54e2c3]
/home/openxs/dbs/p5.1/libexec/mysqld(MYSQLparse(void*)+0xd504) [0x5f5f24]
/home/openxs/dbs/p5.1/libexec/mysqld(parse_sql(THD*, Parser_state*, Object_creation_ctx*)+0x9c) [0x5ddccc]
/home/openxs/dbs/p5.1/libexec/mysqld(mysql_parse(THD*, char*, unsigned int, char const**)+0x45f) [0x5de2bf]
/home/openxs/dbs/p5.1/libexec/mysqld(dispatch_command(enum_server_command, THD*, char*, unsigned int)+0xa88) [0x5dee18]
/home/openxs/dbs/p5.1/libexec/mysqld(do_command(THD*)+0x126) [0x5dfb46]
/home/openxs/dbs/p5.1/libexec/mysqld(handle_one_connection+0x32d) [0x5d16cd]
/lib/x86_64-linux-gnu/libpthread.so.0(+0x7f8e) [0x7fdbde72af8e]
/lib/x86_64-linux-gnu/libc.so.6(clone+0x6d) [0x7fdbdd5f0a0d]

Trying to get some variables.
Some pointers may be invalid and cause the dump to abort.
Query (7fdbd00049c0): SELECT GROUP_CONCAT('\\\\\n* ', '\'',user,'\'@\'',host,'\'' ORDER BY user, host) AS user_spec FROM mysql.user
Connection ID (thread ID): 2
Status: NOT_KILLED