From e3dd9a95e50ef2019435b01bd9e161d552673a28 Mon Sep 17 00:00:00 2001
From: Varun Gupta <varunraiko1803@gmail.com>
Date: Fri, 16 Mar 2018 18:57:21 +0530
Subject: [PATCH] MDEV-6736: Valgrind warnings 'Invalid read' in
 subselect_engine::calc_const_tables with SQ in WHERE and            HAVING,
 ORDER BY, materialization+semijoin

During cleanup a pointer to the materialised table that was freed was not set to NULL
---
 mysql-test/r/having.result | 14 ++++++++++++++
 mysql-test/t/having.test   | 18 ++++++++++++++++++
 sql/sql_select.cc          |  4 +++-
 3 files changed, 35 insertions(+), 1 deletion(-)

diff --git a/mysql-test/r/having.result b/mysql-test/r/having.result
index 0b933427303..c509458d830 100644
--- a/mysql-test/r/having.result
+++ b/mysql-test/r/having.result
@@ -723,4 +723,18 @@ SELECT * FROM t1 JOIN t2 ON c1 = c2 HAVING c2 > 'a' ORDER BY c2 LIMIT 1;
 c1	c2
 x	x
 DROP TABLE t1,t2;
+#
+# MDEV-6736: Valgrind warnings 'Invalid read' in subselect_engine::calc_const_tables with SQ 
+# in WHERE and HAVING, ORDER BY, materialization+semijoin
+#
+CREATE TABLE t1 (a INT) ENGINE=MyISAM;
+INSERT INTO t1 VALUES (3),(8);
+CREATE TABLE t2 (b INT) ENGINE=MyISAM;
+INSERT INTO t2 VALUES (2),(1);
+SELECT a FROM t1
+WHERE 9 IN ( SELECT MIN( a ) FROM t1 )
+HAVING a <> ( SELECT COUNT(*) FROM t2 ) 
+ORDER BY a;
+a
+DROP TABLE t1,t2;
 End of 10.0 tests
diff --git a/mysql-test/t/having.test b/mysql-test/t/having.test
index 1682fe5b874..51cf3fb426d 100644
--- a/mysql-test/t/having.test
+++ b/mysql-test/t/having.test
@@ -759,4 +759,22 @@ SELECT * FROM t1 JOIN t2 ON c1 = c2 HAVING c2 > 'a' ORDER BY c2 LIMIT 1;
 
 DROP TABLE t1,t2;
 
+--echo #
+--echo # MDEV-6736: Valgrind warnings 'Invalid read' in subselect_engine::calc_const_tables with SQ 
+--echo # in WHERE and HAVING, ORDER BY, materialization+semijoin
+--echo #
+
+CREATE TABLE t1 (a INT) ENGINE=MyISAM;
+INSERT INTO t1 VALUES (3),(8);
+
+CREATE TABLE t2 (b INT) ENGINE=MyISAM;
+INSERT INTO t2 VALUES (2),(1);
+
+SELECT a FROM t1
+WHERE 9 IN ( SELECT MIN( a ) FROM t1 )
+HAVING a <> ( SELECT COUNT(*) FROM t2 ) 
+ORDER BY a;
+
+DROP TABLE t1,t2;
+
 --echo End of 10.0 tests
diff --git a/sql/sql_select.cc b/sql/sql_select.cc
index fd8ff6eb016..37d68c730dd 100644
--- a/sql/sql_select.cc
+++ b/sql/sql_select.cc
@@ -11476,13 +11476,15 @@ void JOIN_TAB::cleanup()
       }
       else
       {
+        TABLE_LIST *tmp= table->pos_in_table_list;
         end_read_record(&read_record);
-        table->pos_in_table_list->jtbm_subselect->cleanup();
+        tmp->jtbm_subselect->cleanup();
         /* 
           The above call freed the materializedd temptable. Set it to NULL so
           that we don't attempt to touch it if JOIN_TAB::cleanup() is invoked
           multiple times (it may be)
         */
+        tmp->table= NULL;
         table=NULL;
       }
       DBUG_VOID_RETURN;