From 06ec7a1d7646833cac76516fe78a23577cdb4a8a Mon Sep 17 00:00:00 2001
From: Zefan Li <lizefan@huawei.com>
Date: Tue, 9 Aug 2016 11:25:01 +0800
Subject: [PATCH] cpuset: make sure new tasks conform to the current config of
the cpuset
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(+)
diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index 11eaf14b52c2..e120bd983ad0 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -2074,6 +2074,20 @@ static void cpuset_bind(struct cgroup_subsys_state *root_css)
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, ¤t->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,
};
--
2.34.1