The io_submit_one function in fs/aio.c in the Linux kernel before 2.6.23 allows local users to cause a denial of service (NULL pointer dereference) via a crafted io_submit system call with an IOCB_FLAG_RESFD flag.
https://bugzilla.redhat.com/show_bug.cgi?id=631716
http://www.vmware.com/security/advisories/VMSA-2011-0012.html
http://www.securityfocus.com/archive/1/520102/100/0/threaded
http://www.redhat.com/support/errata/RHSA-2010-0839.html
http://www.kernel.org/pub/linux/kernel/v2.6/ChangeLog-2.6.23
http://securitytracker.com/id?1024708