FreeBSD Security Advisory – Due to the interaction between devfs and VFS, a race condition exists where the kernel might dereference a NULL pointer.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/81791/FreeBSD-SA-09-14.devfs.txt
Source: https://packetstormsecurity.com/files/81791/FreeBSD-Security-Advisory-Devfs-VFS.html