Hi Dave,
I build the proccgroup extensions on
https://people.redhat.com/anderson/extensions/proccgroup.c.
and find a bug on centos 7. the following patch fix it.
I also want to ask another question: 
Why not put various extensions in the extensions directory of the source code?
Wang Long (1):
  extensions: proccgroup: fix the wrong method which detect whether to
    support getting subsys name
 extensions/proccgroup.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
-- 
1.8.3.1