Linux kernel 2.6 and 2.4 on the IA64 architecture allows local users to cause a denial of service (kernel crash) via ptrace and the restore_sigcontext function.
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A10487
http://www.vupen.com/english/advisories/2005/1878
http://www.securityfocus.com/bid/14051
http://www.securityfocus.com/archive/1/427980/100/0/threaded
http://www.redhat.com/support/errata/RHSA-2005-663.html
http://www.redhat.com/support/errata/RHSA-2005-551.html
http://www.redhat.com/support/errata/RHSA-2005-514.html
http://www.novell.com/linux/security/advisories/2005_44_kernel.html
http://www.kernel.org/pub/linux/kernel/v2.6/ChangeLog-2.6.12.1
http://www.debian.org/security/2006/dsa-1018
http://www.debian.org/security/2005/dsa-922
http://securitytracker.com/id?1014275
http://secunia.com/advisories/19369
http://secunia.com/advisories/18056
http://secunia.com/advisories/17073