Another app is currently holding the yum lock, currentlyyum

Another app is currently holding the yum lock, currentlyyum
When you run the yum command on fedora, the prompt "Another app is currently holding the yum lock" is sometimes displayed, as shown in:
 
1) What is going on? According to the prompt, an update is already running in the system process. View in the process: ps-ef | grep update

2) kill the process to kill the process. After killing the process, the error persists. In the original/var/run directory, there is also the yum process ID, which needs to be forcibly deleted:
 
3) restart the yum Update Service as follows:

4) Restart yum-y install gcc * gcc-c ++ * autoconf * automake * zlib * libxml * ncurses-devel * libmcrypt * libtool *.