Bug #37362: Crash in do_field_eq

EXPLAIN EXTENDED of nested query containing a error:

   1054 Unknown column '...' in 'field list'

may cause a server crash.


Parse error like described above forces a call to
JOIN::destroy() on malformed subquery.
That JOIN::destroy function closes and frees temporary
tables. However, temporary fields of these tables
may be listed in st_select_lex::group_list of outer
query, and that st_select_lex may not cleanup them
properly. So, after the JOIN::destroy call that
st_select_lex::group_list may have Item_field
objects with dangling pointers to freed temporary
table Field objects. That caused a crash.

mysql-test/r/subselect3.result

@@ -849,4 +849,23 @@ ROW(1,2) = (SELECT    1,    1)	ROW(1,2) IN (SELECT    1,    1)
 SELECT ROW(1,2) = (SELECT    1,    2), ROW(1,2) IN (SELECT    1,    2);
 ROW(1,2) = (SELECT    1,    2)	ROW(1,2) IN (SELECT    1,    2)
 1	1
+CREATE TABLE t1 (a INT, b INT, c INT);
+INSERT INTO t1 VALUES (1,1,1), (1,1,1);
+EXPLAIN EXTENDED 
+SELECT c FROM 
+( SELECT 
+(SELECT COUNT(a) FROM 
+(SELECT COUNT(b) FROM t1) AS x GROUP BY c
+) FROM t1 GROUP BY b
+) AS y;
+ERROR 42S22: Unknown column 'c' in 'field list'
+SHOW WARNINGS;
+Level	Code	Message
+Note	1276	Field or reference 'test.t1.a' of SELECT #3 was resolved in SELECT #2
+Note	1276	Field or reference 'test.t1.c' of SELECT #3 was resolved in SELECT #2
+Error	1054	Unknown column 'c' in 'field list'
+Note	1003	select `c` AS `c` from (select (select count(`test`.`t1`.`a`) AS `COUNT(a)` from (select count(`test`.`t1`.`b`) AS `COUNT(b)` from `test`.`t1`) `x` group by `c`) AS `(SELECT COUNT(a) FROM 
+(SELECT COUNT(b) FROM t1) AS x GROUP BY c
+)` from `test`.`t1` group by `test`.`t1`.`b`) `y`
+DROP TABLE t1;
 End of 5.0 tests

mysql-test/t/subselect3.test

@@ -669,4 +669,23 @@ SELECT ROW(1,2) = (SELECT NULL,    1), ROW(1,2) IN (SELECT NULL,    1);
 SELECT ROW(1,2) = (SELECT    1,    1), ROW(1,2) IN (SELECT    1,    1);
 SELECT ROW(1,2) = (SELECT    1,    2), ROW(1,2) IN (SELECT    1,    2);
 
+#
+# Bug #37362      Crash in do_field_eq
+#
+CREATE TABLE t1 (a INT, b INT, c INT);
+INSERT INTO t1 VALUES (1,1,1), (1,1,1);
+
+--error 1054
+EXPLAIN EXTENDED 
+  SELECT c FROM 
+    ( SELECT 
+      (SELECT COUNT(a) FROM 
+        (SELECT COUNT(b) FROM t1) AS x GROUP BY c
+      ) FROM t1 GROUP BY b
+    ) AS y;
+SHOW WARNINGS;
+
+DROP TABLE t1;
+
+
 --echo End of 5.0 tests

sql/sql_select.cc

@@ -2161,6 +2161,14 @@ JOIN::destroy()
   cond_equal= 0;
 
   cleanup(1);
+ /* Cleanup items referencing temporary table columns */
+  if (!tmp_all_fields3.is_empty())
+  {
+    List_iterator_fast<Item> it(tmp_all_fields3);
+    Item *item;
+    while ((item= it++))
+      item->cleanup();
+  }
   if (exec_tmp_table1)
     free_tmp_table(thd, exec_tmp_table1);
   if (exec_tmp_table2)