THREAD_GROUP and linux thread

["Hua Zhong" <hzhong@cisco.com>]

Hi:
 
I am making some kernel changes to keep track of threads. Basically I
want to maintain a linked list of all threads.
 
The linux thread library on my system doesn't make use of the
CLONE_THREAD flag, so the thread_group list is not being used. I can
just add a new field in task_struct and maintain the list in
fork.c/exec.c/exit.c exactly as what the kernel does to the thread_group
list, but I am just wondering if I could just change the kernel to treat
CLONE_VM the same way as CLONE_THREAD which is a much simpler change.
 
So my questions are:
 
1. Is it safe to do so? [ in other word, is it a requirement to use
CLONE_VM together with CLONE_THREAD ]
2. Which version of pthread uses the CLONE_THREAD flag?
 
I couldn't find the documentation about CLONE_THREAD usages, so your
reply is very much appreciated.
 
Hua