On Mon, Sep 26, 2016 at 02:34:33PM +0200, Takashi Iwai wrote:

On Thu, 22 Sep 2016 19:29:08 +0200,
Greg Kroah-Hartman wrote:

quoted

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

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

From: Zefan Li <redacted>

commit 06f4e94898918bcad00cdd4d349313a439d6911e upstream.

A new task inherits cpus_allowed and mems_allowed masks from its parent,
but if someone changes cpuset's config by writing to cpuset.cpus/cpuset.mems
before this new task is inserted into the cgroup's task list, the new task
won't be updated accordingly.

Signed-off-by: Zefan Li <redacted>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 kernel/cpuset.c |   15 +++++++++++++++
 1 file changed, 15 insertions(+)

--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c

@@ -2074,6 +2074,20 @@ static void cpuset_bind(struct cgroup_su
 	mutex_unlock(&cpuset_mutex);
 }
 
+/*
+ * Make sure the new task conform to the current state of its parent,
+ * which could have been changed by cpuset just after it inherits the
+ * state from the parent and before it sits on the cgroup's task list.
+ */
+void cpuset_fork(struct task_struct *task)

This causes a build warning:

  kernel/cpuset.c:2101:2: warning: (near initialization for 'cpuset_cgrp_subsys.fork') [enabled by default]
  .fork  = cpuset_fork,
  ^

where fork op in 4.4 kernel has still priv argument that was dropped
recently.

Thanks, I have a patch in my tree already for this and it will show up
in the next release.

greg k-h