Assertion `tab->ref.use_count' failed on query with joins, constant table, multi-part key

mysqld: 5.5/sql/sql_select.cc:17536: void join_read_key_unlock_row(st_join_table*): Assertion `tab->ref.use_count' failed.

140725  1:26:23 [ERROR] mysqld got signal 6 ;

#6  0x00007fdb57762621 in *__GI___assert_fail (assertion=0xd98f8b "tab->ref.use_count", file=<optimized out>, line=17536, function=0xd9a660 "void join_read_key_unlock_row(st_join_table*)") at assert.c:81

#7  0x000000000068b280 in join_read_key_unlock_row (tab=0x7fdb521b8fe8) at 5.5/sql/sql_select.cc:17536

#8  0x000000000068a224 in evaluate_join_record (join=0x7fdb52181600, join_tab=0x7fdb521b8fe8, error=0) at 5.5/sql/sql_select.cc:17089

#9  0x0000000000689a1d in sub_select (join=0x7fdb52181600, join_tab=0x7fdb521b8fe8, end_of_records=false) at 5.5/sql/sql_select.cc:16839

#10 0x000000000068927b in do_select (join=0x7fdb52181600, fields=0x7fdb521819c0, table=0x0, procedure=0x0) at 5.5/sql/sql_select.cc:16501

#11 0x00000000006681af in JOIN::exec (this=0x7fdb52181600) at 5.5/sql/sql_select.cc:2873

#12 0x00000000006689b9 in mysql_select (thd=0x7fdb55f49060, rref_pointer_array=0x7fdb55f4ccc8, tables=0x7fdb52148358, wild_num=0, fields=..., conds=0x7fdb52181280, og_num=1, order=0x0, group=0x7fdb521814f8, having=0x0, proc_param=0x0, select_options=2147748608, result=0x7fdb521815e0, unit=0x7fdb55f4c380, select_lex=0x7fdb55f4ca58) at 5.5/sql/sql_select.cc:3094

#13 0x000000000065f489 in handle_select (thd=0x7fdb55f49060, lex=0x7fdb55f4c2d0, result=0x7fdb521815e0, setup_tables_done_option=0) at 5.5/sql/sql_select.cc:319

#14 0x0000000000638a9f in execute_sqlcom_select (thd=0x7fdb55f49060, all_tables=0x7fdb52148358) at 5.5/sql/sql_parse.cc:4688

#15 0x0000000000631c81 in mysql_execute_command (thd=0x7fdb55f49060) at 5.5/sql/sql_parse.cc:2233

#16 0x000000000063b1ae in mysql_parse (thd=0x7fdb55f49060, rawbuf=0x7fdb52148078 "SELECT i2 FROM t1 AS t1a STRAIGHT_JOIN ( t2 INNER JOIN t1 AS t1b ON (t1b.c1 = c2) ) ON (t1b.i1 = pk2 ) \nWHERE t1a.c1 = c2 GROUP BY i2", length=133, parser_state=0x7fdb52bb5630) at 5.5/sql/sql_parse.cc:5799

#17 0x000000000062f1f9 in dispatch_command (command=COM_QUERY, thd=0x7fdb55f49060, packet=0x7fdb532fa061 "", packet_length=133) at 5.5/sql/sql_parse.cc:1079

#18 0x000000000062e385 in do_command (thd=0x7fdb55f49060) at 5.5/sql/sql_parse.cc:793

#19 0x000000000072ffea in do_handle_one_connection (thd_arg=0x7fdb55f49060) at 5.5/sql/sql_connect.cc:1266

#20 0x000000000072faa9 in handle_one_connection (arg=0x7fdb55f49060) at 5.5/sql/sql_connect.cc:1181

#21 0x0000000000b64ee9 in pfs_spawn_thread (arg=0x7fdb53ffa8e0) at 5.5/storage/perfschema/pfs.cc:1015

#22 0x00007fdb58cc2b50 in start_thread (arg=<optimized out>) at pthread_create.c:304

#23 0x00007fdb57811a7d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112

revision-id: jplindst@mariadb.org-20140724113509-r06tvyhubva3gfgn

revno: 4237

branch-nick: 5.5

CREATE TABLE t1 (i1 INT, c1 VARCHAR(1)) ENGINE=MyISAM;

INSERT INTO t1 VALUES (6,'b');

CREATE TABLE t2 (pk2 INT, i2 INT, c2 VARCHAR(1), PRIMARY KEY(pk2), KEY(pk2,i2)) ENGINE=MyISAM;

INSERT INTO t2 VALUES (1,2,'s'),(2,4,'r'),(3,8,'m'),(4,4,'b'),(5,4,'x'),(6,7,'g'),(7,4,'p');

SELECT i2 FROM t1 AS t1a STRAIGHT_JOIN ( t2 INNER JOIN t1 AS t1b ON (t1b.c1 = c2) ) ON (t1b.i1 = pk2 ) 

WHERE t1a.c1 = c2 GROUP BY i2;

EXPLAIN EXTENDED

SELECT i2 FROM t1 AS t1a STRAIGHT_JOIN ( t2 INNER JOIN t1 AS t1b ON (t1b.c1 = c2) ) ON (t1b.i1 = pk2 ) 

WHERE t1a.c1 = c2 GROUP BY i2;

id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra

1	SIMPLE	t1a	system	NULL	NULL	NULL	NULL	1	100.00	

1	SIMPLE	t1b	system	NULL	NULL	NULL	NULL	1	100.00	

1	SIMPLE	t2	ref	PRIMARY,pk2	pk2	4	const	1	100.00	Using where

Warnings:

Note	1003	select `test`.`t2`.`i2` AS `i2` from `test`.`t2` join `test`.`t1` `t1b` where ((`test`.`t2`.`c2` = 'b') and (`test`.`t2`.`pk2` = 6)) group by `test`.`t2`.`i2`