Bug#21136 CREATE TABLE SELECT within CREATE TABLE SELECT causes server crash

When CREATE TEMPORARY TABLE .. SELECT is invoked from a stored function
which in turn is called from CREATE TABLE SELECT causes a memory leak
because the inner create temporary table overrides the outter extra_lock
reference when locking the table.

The solution is to simply not overrride the extra_lock by only using the
extra_lock for a non-temporary table lock.

1 files changed, 25 insertions, 0 deletions

diff --git a/mysql-test/t/create.test b/mysql-test/t/create.test
index d4feeebe4b1..023e55ea418 100644
--- a/mysql-test/t/create.test
+++ b/mysql-test/t/create.test
@@ -1303,4 +1303,29 @@ return 0;
 drop view имя_вью_кодировке_утф8_длиной_больше_чем_42;
 drop table имя_таблицы_в_кодировке_утф8_длиной_больше_чем_48;
 set names default;
+
+#
+# Bug#21136 CREATE TABLE SELECT within CREATE TABLE SELECT causes server crash
+#
+
+--disable_warnings
+drop table if exists t1,t2,t3;
+drop function if exists f1;
+--enable_warnings
+
+--delimiter |
+create function f1() returns int
+begin
+  declare res int;
+  create temporary table t3 select 1 i;
+  set res:= (select count(*) from t1);
+  drop temporary table t3;
+  return res;
+end|
+--delimiter ;
+create table t1 as select 1;
+create table t2 as select f1() from t1;
+drop table t1,t2;
+drop function f1;
+
 --echo End of 5.1 tests