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

Existing lock /var/run/yum.pid: another copy is running as pid 2619.
Another app is currently holding the yum lock; waiting for it to exit...
  The other application is: yum
    Memory :  64 M RSS (901 MB VSZ)
    Started: Mon Jun  9 22:38:34 2014 - 18:21 ago
    State  : Traced/Stopped, pid: 2619
Another app is currently holding the yum lock; waiting for it to exit...
  The other application is: yum
    Memory :  64 M RSS (901 MB VSZ)
    Started: Mon Jun  9 22:38:34 2014 - 18:23 ago
    State  : Traced/Stopped, pid: 2619
Another app is currently holding the yum lock; waiting for it to exit...
  The other application is: yum
    Memory :  64 M RSS (901 MB VSZ)
    Started: Mon Jun  9 22:38:34 2014 - 18:25 ago
    State  : Traced/Stopped, pid: 2619

删除 rm -f /var/run/yum.pid再次运行