mysqld can't start without any info
the answer is there MySQL can not write to the directory you are pointing inside my.cnf, and it dose not have the right permissions. to fix this problem make sure the user MySQL has owner privileges on the directory that my.cnf is pointing for example lets say the base_dir is located under /MySQL , data_dir is located under /MySQL/data and the socket is located under /tmp in this example you need to make sure /MySQL and /MySQL/data are owned by MySQL user, for /tmp since its a default directory for Linux user MySQL should have read,write and execute privileges. also you need to make sure the partition that contain the data_dir is not full "contain enough free space"