“wati for commit lock" occur in mysql5.6.19 slave

When full backup with percona-xtrabackup 2.2.4 in mysql 5.6.19 slave,I found that:
mysql> show processlist;
±--------±-------------±---------------------±-------------±--------±-------±---------------------------------------±------------------+
| Id | User | Host | db | Command | Time | State | Info |
±--------±-------------±---------------------±-------------±--------±-------±---------------------------------------±------------------+
| 716140 | system user | | NULL | Connect | 830477 | Queueing master event to the relay log | NULL |
| 944563 | system user | | NULL | Connect | 911 | Waiting for commit lock | NULL |
| 1019137 | px224db | 10.19.83.19:57272 | px224db | Sleep | 6 | | NULL |
| 1019214 | root | localhost | mysql | Query | 904 | init | SHOW SLAVE STATUS |
| 1019228 | monit11 | 10.18.67.10:49936 | NULL | Query | 872 | init | SHOW SLAVE STATUS |
| 1019229 | monit11 | 10.18.67.10:49962 | NULL | Query | 872 | init | SHOW SLAVE STATUS |
| 1019233 | monit11 | 10.18.67.10:50025 | NULL | Query | 872 | init | SHOW SLAVE STATUS |

I know it’s a bug in mysql5.6.10,and has been resolved in mysql 5.6.13; why occured in mysql 5.6.19 and how to solved the problem?
Thank you.

Hi,

It seems, that bug still exists. Please check and keep monitor below bugs for further progress.
http://bugs.mysql.com/bug.php?id=70307
https://bugs.launchpad.net/percona-server/+bug/1295820
https://bugs.launchpad.net/percona-server/+bug/1386363