Patch "cpuset: make sure new tasks conform to the current config of the cpuset" has been added to the 4.4-stable tree

Patch "cpuset: make sure new tasks conform to the current config of the cpuset" has been added to the 4.4-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    cpuset: make sure new tasks conform to the current config of the cpuset

to the 4.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     cpuset-make-sure-new-tasks-conform-to-the-current-config-of-the-cpuset.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 06f4e94898918bcad00cdd4d349313a439d6911e Mon Sep 17 00:00:00 2001
From: Zefan Li <lizefan@huawei.com>
Date: Tue, 9 Aug 2016 11:25:01 +0800
Subject: cpuset: make sure new tasks conform to the current config of the cpuset

From: Zefan Li <lizefan@huawei.com>

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 <lizefan@huawei.com>
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)
+{
+	if (task_css_is_root(task, cpuset_cgrp_id))
+		return;
+
+	set_cpus_allowed_ptr(task, &current->cpus_allowed);
+	task->mems_allowed = current->mems_allowed;
+}
+
 struct cgroup_subsys cpuset_cgrp_subsys = {
 	.css_alloc	= cpuset_css_alloc,
 	.css_online	= cpuset_css_online,
@@ -2084,6 +2098,7 @@ struct cgroup_subsys cpuset_cgrp_subsys
 	.attach		= cpuset_attach,
 	.post_attach	= cpuset_post_attach,
 	.bind		= cpuset_bind,
+	.fork		= cpuset_fork,
 	.legacy_cftypes	= files,
 	.early_init	= 1,
 };


Patches currently in stable-queue which might be from lizefan@huawei.com are

queue-4.4/cpuset-make-sure-new-tasks-conform-to-the-current-config-of-the-cpuset.patch