On Sat, Mar 21, 2015 at 10:25:56PM +1100, Aleksa Sarai wrote:

quoted

Also, what pins the cset between task_css_set() and get_css_set()?
task_css_set() is protected by RCU and the above should have triggered
RCU warning if the debug option is enabled.  Please always test with
the debug options enabled, especially the lockdep and RCU ones.

Debug was enabled AFAIK and I didn't get anything in `dmesg`. I've fixed it
anyway.

So, this is worrying.  If you have RCU debugging enabled, it should
have triggered the warning.  If it hadn't, maybe there's something
else protecting it and we don't need the extra rcu locking around it.
Can you please investigate what's going on?

Thanks.

-- 
tejun