Flaw bug created to hold information about an old flaw we knew something about. For more details see the MITRE CVE description.
MITRE description: Linux kernel before 2.6.16.5 does not properly handle uncanonical return addresses on Intel EM64T CPUs, which reports an exception in the SYSRET instead of the next instruction, which causes the kernel exception handler to run on the user stack with the wrong GS.