FreeBSD Security Advisory FreeBSD-SA-04:11.msync – Programming errors in the implementation of the msync(2) system call involving the MS_INVALIDATE operation lead to cache consistency problems between the virtual memory system and on-disk contents. In some situations, a user with read access to a file may be able to prevent changes to that file from being committed to disk.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/33429/FreeBSD-SA-04%3A11.msync.txt
Source: https://packetstormsecurity.com/files/33429/FreeBSD-Security-Advisory-2004.11.html