The mprotect code (mprotect.c) in Linux 2.6 on Itanium IA64 Montecito processors does not properly maintain cache coherency as required by the architecture, which allows local users to cause a denial of service and possibly corrupt data by modifying PTE protections.
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A11283
http://www.redhat.com/support/errata/RHSA-2005-514.html
http://www.intel.com/cd/ids/developer/asmo-na/eng/215766.htm
http://www.debian.org/security/2005/dsa-922