I am trying to create a process which can't be killed even by "kill -9", which can be useful in attack-defense mode CTF, I tried this <https://unix.stackexchange.com/questions/134888/simulate-an-unkillable-process-in-d-state> but it seems fixed in kernel after 2.6.25 <http://www.ibm.com/developerworks/library/l-task-killable/> so I wonder if there is any way to create a unkillable process with no-root privilege in linux? thank you. (first time to ask question in stackoverflow...I'm feeling a little nervous...)