On Tue, Feb 20, 2018 at 08:26:59PM +0100, Michael Kerrisk (man-pages) wrote: > Hello Tejun > > According to Documentation/cgroup-v2.txt, a "domain invalid" cgroup > can't have member tasks. And indeed this is generally not permitted. > > However, someone recently showed me a scenario where a "domain > invalid" cgroup can have member processes. See the following example: > > # mkdir -p /sys/fs/cgroup/unified/grp0/grp1 > # sleep 1000 & > [1] 10549 > # echo 10549 > /sys/fs/cgroup/unified/grp0/grp1/cgroup.procs > # echo threaded > /sys/fs/cgroup/unified/grp0/cgroup.type > # cat /sys/fs/cgroup/unified/grp0/cgroup.type > threaded > # cat /sys/fs/cgroup/unified/grp0/grp1/cgroup.type > domain invalid > # cat /sys/fs/cgroup/unified/grp0/grp1/cgroup.threads > 10549 > > From the above, we see that the cgroup grp0/grp1 is of type "domain > invalid" and has a member thread. This seems to be a violation of the > documented rules, and is I assume a bug, since in the above scenario, > we are denied from adding further tasks to the grp0/grp1 cgroup: > > # sleep 2000 & > [2] 10553 > # echo 10553 > /sys/fs/cgroup/unified/grp0/grp1/cgroup.procs > sh: echo: write error: Operation not supported > > Could you comment please? Hmm... nr_populated_domain_children check should have caught that condition and rejected it. Will look into what's going on. Thanks. -- tejun -- To unsubscribe from this list: send the line "unsubscribe cgroups" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
