Messages in this thread | | | Subject | Re: [patch] cgroups: disallow attaching kthreadd | From | Mike Galbraith <> | Date | Wed, 04 Apr 2012 04:34:38 +0200 |
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On Tue, 2012-04-03 at 11:49 -0700, Tejun Heo wrote: > On Tue, Apr 03, 2012 at 07:58:26PM +0200, Mike Galbraith wrote: > > @@ -1894,6 +1895,14 @@ int cgroup_attach_task(struct cgroup *cg > > if (tsk->flags & PF_EXITING) > > return -ESRCH; > > > > + /* > > + * Workqueue threads may acquire PF_THREAD_BOUND and become > > + * trapped in a cpuset, or RT worker may be born in a cgroup > > + * with no rt_runtime allocated. Just say no. > > + */ > > + if (tsk == kthreadd_task) > > + return -EINVAL; > > + > > /* Nothing to do if the task is already in that cgroup */ > > oldcgrp = task_cgroup_from_root(tsk, root); > > if (cgrp == oldcgrp) > > @@ -2172,6 +2181,17 @@ static int attach_task_by_pid(struct cgr > > > > if (threadgroup) > > tsk = tsk->group_leader; > > + > > + /* > > + * Workqueue threads may acquire PF_THREAD_BOUND and become > > + * trapped in a cpuset, or RT worker may be born in a cgroup > > + * with no rt_runtime allocated. Just say no. > > + */ > > + if (tsk == kthreadd_task) { > > + ret = -EINVAL; > > + goto out_unlock_cgroup; > > + } > > If we have this test here, do we need the same check in > cgroup_attach_task()/
It looked to me like yes, because cgroup_attach_task() can be called directly. For the problem at hand, user script doing bad things, no, it's not needed.
-Mike
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