Linux kernel 2.4.x and 2.6.x allows local users to cause a denial of service (CPU and memory consumption) and bypass RLIM_MEMLOCK limits via the mlockall call.
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A9890
http://www.vupen.com/english/advisories/2005/1878
http://www.redhat.com/support/errata/RHSA-2005-663.html
http://www.redhat.com/support/errata/RHSA-2005-092.html
http://secunia.com/advisories/17002
http://lists.grok.org.uk/pipermail/full-disclosure/2005-January/030660.html
http://distro.conectiva.com.br/atualizacoes/index.php?id=a&anuncio=000930