Messages in this thread | | | Date | Tue, 1 Jul 2008 15:17:34 +0530 | From | Dhaval Giani <> | Subject | Re: Attaching PID 0 to a cgroup |
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[put in the wrong alias for containers list correcting it.]
On Tue, Jul 01, 2008 at 03:15:45PM +0530, Dhaval Giani wrote: > Hi Paul, > > Attaching PID 0 to a cgroup caused the current task to be attached to > the cgroup. Looking at the code, > > if (pid) { > rcu_read_lock(); > tsk = find_task_by_vpid(pid); > if (!tsk || tsk->flags & PF_EXITING) { > rcu_read_unlock(); > return -ESRCH; > } > get_task_struct(tsk); > rcu_read_unlock(); > > if ((current->euid) && (current->euid != tsk->uid) > && (current->euid != tsk->suid)) { > put_task_struct(tsk); > return -EACCES; > } > } else { > tsk = current; > get_task_struct(tsk); > } > > I was wondering, why this was done. It seems to be unexpected behavior. > Wouldn't something like the following be a better response? (I've used > EINVAL, but I can change it to ESRCH if that is better.) > > --- > cgroups: Don't allow PID 0 to be attached to a group > > Currently when one trys to attach PID 0 to a cgroup, it attaches > the current task. That is not expected behavior. It should return > an error instead. > > Signed-off-by: Dhaval Giani <dhaval@linux.vnet.ibm.com> > > Index: linux-2.6/kernel/cgroup.c > =================================================================== > --- linux-2.6.orig/kernel/cgroup.c > +++ linux-2.6/kernel/cgroup.c > @@ -1309,8 +1309,7 @@ static int attach_task_by_pid(struct cgr > return -EACCES; > } > } else { > - tsk = current; > - get_task_struct(tsk); > + return -EINVAL; > } > > ret = cgroup_attach_task(cgrp, tsk); > -- > regards, > Dhaval
-- regards, Dhaval
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