diff --git a/mysql-test/mysql-test-run.pl b/mysql-test/mysql-test-run.pl
index 236d925feea..a045441e046 100755
--- a/mysql-test/mysql-test-run.pl
+++ b/mysql-test/mysql-test-run.pl
@@ -2942,11 +2942,6 @@ sub run_mysqltest ($) {
 
   mtr_init_args(\$args);
 
-  if ( $opt_valgrind_mysqltest )
-  {
-    valgrind_arguments($args, \$exe);
-  }
-
   mtr_add_arg($args, "--no-defaults");
   mtr_add_arg($args, "--silent");
   mtr_add_arg($args, "-v");
@@ -3062,6 +3057,17 @@ sub run_mysqltest ($) {
   # Add arguments that should not go into the MYSQL_TEST env var
   # ----------------------------------------------------------------------
 
+  if ( $opt_valgrind_mysqltest )
+  {
+    # Prefix the Valgrind options to the argument list.
+    # We do this here, since we do not want to Valgrind the nested invocations
+    # of mysqltest; that would mess up the stderr output causing test failure.
+    my @args_saved = @$args;
+    mtr_init_args(\$args);
+    valgrind_arguments($args, \$exe);
+    mtr_add_arg($args, "%s", $_) for @args_saved;
+  }
+
   mtr_add_arg($args, "--test-file");
   mtr_add_arg($args, $tinfo->{'path'});
 
diff --git a/mysql-test/r/innodb.result b/mysql-test/r/innodb.result
index e8af68a6067..c5658d22eb6 100644
--- a/mysql-test/r/innodb.result
+++ b/mysql-test/r/innodb.result
@@ -1821,7 +1821,7 @@ Variable_name	Value
 innodb_sync_spin_loops	20
 show variables like "innodb_thread_concurrency";
 Variable_name	Value
-innodb_thread_concurrency	0
+innodb_thread_concurrency	8
 set global innodb_thread_concurrency=1001;
 show variables like "innodb_thread_concurrency";
 Variable_name	Value
diff --git a/mysql-test/t/cast.test b/mysql-test/t/cast.test
index 7e09f44397c..533da542855 100644
--- a/mysql-test/t/cast.test
+++ b/mysql-test/t/cast.test
@@ -171,6 +171,8 @@ select cast(1.0e+300 as signed int);
 CREATE TABLE t1 (f1 double);
 INSERT INTO t1 SET f1 = -1.0e+30 ;
 INSERT INTO t1 SET f1 = +1.0e+30 ;
+# Expected result is +-1e+30, but Windows returns +-1e+030.
+--replace_result 1e+030 1e+30
 SELECT f1 AS double_val, CAST(f1 AS SIGNED INT) AS cast_val FROM t1;
 DROP TABLE t1;