On 07/29/2010 04:35 PM, Nathan Lynch wrote: > On Thu, 2010-07-29 at 14:30 +0200, Daniel Lezcano wrote: > >> 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 ? >> > Well, powertop is used for monitoring and modifying global system > characteristics (e.g. processor C states, USB autosuspend) that don't > make sense to virtualize. Many events in /proc/timer_stats are > accocunted to pid 0 (swapper/idle). I think the question is whether a > pidns-relative slice of timer events will be useful or just confusing. > IMHO I find confusing to see all the applications name/pid running on the whole system (host + containers) from a container. Even if these applications are not accessible, that gives informations to the container on what is running on the system and I think we should consider that as a security breach. We can just "hide" the content of this file for a pid namespace different of the init pid namespace, but that may suppress the possibility to investigate with powertop the consumption of a specific appliance, as accurate as it could be... Thanks -- Daniel _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/containers
