pid namespace isolation broken with powertop

[Daniel Lezcano <daniel.lezcano-GANU6spQydw@public.gmane.org>]

Hi all,

I noticed all the tasks of the host are listed in /proc/timer_stats
These information is not virtualized neither isolated within a container.

I was expecting to see only the tasks in the container with the 
corresponding pids.

I am not sure this is something critical, but the usage of powertop in 
the container shows all the tasks of the system.

While looking at the code in kernel/time/timer.c, it is not obvious to 
fix this isolation because it is the pid number which is stored in a 
list, so there is not enough informations to discriminate the pid 
namespace against the current one.

I am wondering if:

  1) is it worth to isolate these informations ? (IMHO, yes).
  2) should the stats be stored per pid namespace or adding an hash 
value + pid namespace as a key in the timer stats list ?

Thanks
   -- Daniel