The WPAR system call implementation in the kernel in IBM AIX 6.1 allows local users to cause a denial of service via unknown calls that trigger "undefined behavior."
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A6198
http://www14.software.ibm.com/webapp/set2/subscriptions/pqvcmjd?mode=18&ID=4155
http://www14.software.ibm.com/webapp/set2/subscriptions/pqvcmjd?mode=18&ID=4154
http://www14.software.ibm.com/webapp/set2/subscriptions/pqvcmjd?mode=18&ID=4153
http://www.vupen.com/english/advisories/2008/0865
http://www.securityfocus.com/bid/28467
http://www.ibm.com/support/docview.wss?uid=isg1IZ13392