Another app is currently holding the Yum lock

When executing the Yum command on Fedora, sometimes the another app is currently holding the Yum lock prompt, as shown in:

1) What's going on? According to the hint, it turns out that the system process already has an update running. In the process view under: Ps-ef | grep update

2) Kill the process through kill, can be killed, the error is still. Originally in the/var/run directory, there is the Yum process ID, which needs to be forced to delete the process ID file:

3) Restart the Yum update service at the same time, as follows:

4) finally re-yum-y install gcc* gcc-c++* autoconf* automake* zlib* libxml* ncurses-devel* libmcrypt* libtool*, has been normal

Another app is currently holding the Yum lock