Double free vulnerability in the ioctx_alloc function in fs/aio.c in the Linux kernel before 3.12.4 allows local users to cause a denial of service (system crash) or possibly have unspecified other impact via vectors involving an error condition in the aio_setup_ring function.
https://github.com/torvalds/linux/commit/d558023207e008a4476a3b7bb8706b2a2bf5d84f
http://www.openwall.com/lists/oss-security/2014/03/31/10
http://www.kernel.org/pub/linux/kernel/v3.x/ChangeLog-3.12.4