yum --- 提示Another app is currently holding the yum lock; waiting for it to exit...

使用yum安装计划任务功能，结果提示：

# yum -y install ntpdate
Loaded plugins: fastestmirror, refresh-packagekit, security
Existing lock /var/run/yum.pid: another copy is running as pid 25960.
Another app is currently holding the yum lock; waiting for it to exit...

直接kill掉之前的进程后重新执行即可：

kill -9 25960
yum install -y ntpdate