The nodev mount option specifies that the filesystem cannot contain special devices. Since the /dev/shm filesystem is not intended to support devices, set this option to ensure that users cannot attempt to create special devices in /dev/shm partitions.
Edit the /etc/fstab file and add nodev to the fourth field (mounting options) for the /dev/shm partition. See the fstab(5) manual page for more information. Run the following command to remount /dev/shm: # mount -o remount,nodev /dev/shm