Bug #21771 Stop slave statement does not stop a running slave

Description:
I have configured a server as a backup server to mysql using replication.
Everyday the slave mysql is started or stopped at a predefined time using cron. The problem is the stop slave statement does not stop the running slave. Here's the output of the show processlist:

mysql> show processlist;
+------+-------------+-----------+-------+---------+-------+----------------------------------+------------------------+
| Id   | User        | Host      | db    | Command | Time  | State               | Info                   |
+------+-------------+-----------+-------+---------+-------+----------------------------------+------------------------+
| 2241 | system user |           | NULL  | Connect | 12001 | Slave: waiting for binlog update | NULL                   |
| 2507 | system user |           | NULL  | Connect | 55244 | Waiting for slave mutex on exit  | NULL                   |
| 2678 | root        | localhost | mysql | Query   | 12043 | Killing slave               | stop slave io_thread   |
| 2677 | root        | localhost | mysql | Query   | 12043 | Killing slave               | stop slave sql_thread  |
| 2701 | root        | localhost | mysql | Query   | 6645  | NULL               | start slave sql_thread |
| 2821 | root        | localhost | NULL  | Query   | 927   | Killing slave               | stop slave             |
| 2834 | root        | localhost | NULL  | Query   | 0     | NULL               | show processlist       |
+------+-------------+-----------+-------+---------+-------+----------------------------------+------------------------+
7 rows in set (0.00 sec)

Any ideas?

How to repeat:
Not sure!

Thank you for taking the time to report a problem.  Unfortunately you are not using a current version of the product you reported a problem with -- the problem might already be fixed. Please download a new version from http://www.mysql.com/downloads/

If you are able to reproduce the bug with one of the latest versions, please change the version on this bug report to the version you tested and change the status back to "Open".  Again, thank you for your continued support of MySQL.