cpuset: initialize effective masks when clone_children is enabled

[ Upstream commit 790317e1b266c776765a4bdcedefea706ff0fada ]

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@gmail.com>
Reported-by: Serge Hallyn <serge.hallyn@ubuntu.com>
Cc: <stable@vger.kernel.org> # 3.17+
Signed-off-by: Zefan Li <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Tested-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>

diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index 1f107c7..7e59b7b 100644 (file)
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -1991,7 +1991,9 @@ static int cpuset_css_online(struct cgroup_subsys_state *css)
 
        mutex_lock(&callback_mutex);
        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);
        mutex_unlock(&callback_mutex);
 out_unlock:
        mutex_unlock(&cpuset_mutex);