The fallocate implementation in the GFS2 filesystem in the Linux kernel before 3.2 relies on the page cache, which might allow local users to cause a denial of service by preallocating blocks in certain situations involving insufficient memory.
https://www.redhat.com/archives/cluster-devel/2011-September/msg00064.html
https://oss.oracle.com/git/?p=redpatch.git%3Ba=commit%3Bh=fadca7bdc43b02f518585d9547019966415cadfd
https://github.com/torvalds/linux/commit/64dd153c83743af81f20924c6343652d731eeecb