The cifs_lookup function in fs/cifs/dir.c in the Linux kernel before 3.2.10
allows local users to cause a denial of service (OOPS) via attempted access
to a special file, as demonstrated by a FIFO.
"The cifs code will attempt to open files on lookup under certain
circumstances. What happens though if we find that the file we opened
was actually a FIFO or other special file? Currently, the open
filehandle just ends up being leaked leading to a dentry refcount
mismatch and oops on umount."

A flaw was discovered in the Linux kernel's cifs file system. An
unprivileged local user could exploit this flaw to crash the system leading
to a denial of service.