+ Check on top of which device this label is configured .
$ ls -ltr /dev/oracleasm/disks/*
$ cat /proc/partitions
If I remember correctly than SELinux can cause such strange issues.
I suggest the following:
Verify /etc/selinux/config and set it to disabled, then restart the system.
Verify you have oracleasmlib installed: yum list oracleasmlib