choose_new_parent in Linux kernel before 2.6.11.12 includes certain debugging code, which allows local users to cause a denial of service (panic) by causing certain circumstances involving termination of a parent process.
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A11235
https://bugzilla.redhat.com/bugzilla/attachment.cgi?id=127302
http://www.ubuntu.com/usn/usn-302-1
http://www.securityfocus.com/bid/18099
http://www.redhat.com/support/errata/RHSA-2006-0493.html
http://www.novell.com/linux/security/advisories/2006_42_kernel.html
http://www.debian.org/security/2006/dsa-1184
http://support.avaya.com/elmodocs2/security/ASA-2006-161.htm
http://secunia.com/advisories/22093
http://secunia.com/advisories/21745
http://secunia.com/advisories/21179