mysql 5.6.22 mirgate to mariadb 10.0.22, slave stop not error

hello ,all
we migrating mysql 5.6.22 (gtid) to mariadb 10.0.22, use three machine:
A: mysql 5.6.22 (gtid) , master
B: mariadb 10.0.22 , slave of A (use Fusion IO)
C: mairadb 10.0.22 , slave of B (use Fusion IO)

First run xtrabackup at A machine, recover to B machine , start slave normal at B.
Then run xtrabackup at B machine, recover to C machine, start slave normal at begin, After 10 minutes , slave thread status is YES, but Exec_Master_Log_Pos value not change.
if run stop slave , not response. but run ddl, dml statement normal .
error log file not error also.

when run /etc/init.d/mysql stop , mysql not stop . only kill -9 `pidof mysql`
after start mysql, run start slave normal . but only normal about 10 minutes. The same question before

when run show slave status \G , red row value not change
Master_Log_File: mysql-bin.000049
Read_Master_Log_Pos: 703551739 # value change
Relay_Log_File: relay-bin.000002
Relay_Log_Pos: 293817098
Relay_Master_Log_File: mysql-bin.000046
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
Exec_Master_Log_Pos: 532843833 # value not change
Relay_Log_Space: 3683986049 # value change
Seconds_Behind_Master: 10602 # value increase