[PATCH 3.19 054/123] cpuset: initialize effective masks when clone_children is enabled

[Greg Kroah-Hartman]

3.19-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Zefan Li <lizefan@xxxxxxxxxx>

commit 790317e1b266c776765a4bdcedefea706ff0fada upstream.

If clone_children is enabled, effective masks won't be initialized
due to the bug:

  # mount -t cgroup -o cpuset xxx /mnt
  # echo 1 > cgroup.clone_children
  # mkdir /mnt/tmp
  # cat /mnt/tmp/
  # cat cpuset.effective_cpus

  # cat cpuset.cpus
  0-15

And then this cpuset won't constrain the tasks in it.

Either the bug or the fix has no effect on unified hierarchy, as
there's no clone_chidren flag there any more.

Reported-by: Christian Brauner <christianvanbrauner@xxxxxxxxx>
Reported-by: Serge Hallyn <serge.hallyn@xxxxxxxxxx>
Signed-off-by: Zefan Li <lizefan@xxxxxxxxxx>
Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
Tested-by: Serge Hallyn <serge.hallyn@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 kernel/cpuset.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -1992,7 +1992,9 @@ static int cpuset_css_online(struct cgro
 
 	spin_lock_irq(&callback_lock);
 	cs->mems_allowed = parent->mems_allowed;
+	cs->effective_mems = parent->mems_allowed;
 	cpumask_copy(cs->cpus_allowed, parent->cpus_allowed);
+	cpumask_copy(cs->effective_cpus, parent->cpus_allowed);
 	spin_unlock_irq(&callback_lock);
 out_unlock:
 	mutex_unlock(&cpuset_mutex);


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