Race condition in the ext4_file_write_iter function in fs/ext4/file.c in the Linux kernel through 3.17 allows local users to cause a denial of service (file unavailability) via a combination of a write action and an F_SETFL fcntl operation for the O_DIRECT flag. http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2014-8086
