cpuset: fix a race condition in __cpuset_node_allowed_softwall()
commit 99afb0fd5f05aac467ffa85c36778fec4396209b upstream.
It's not safe to access task's cpuset after releasing task_lock().
Holding callback_mutex won't help.
Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index e372d94..4b843ac 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -2338,9 +2338,9 @@
task_lock(current);
cs = nearest_hardwall_ancestor(task_cs(current));
+ allowed = node_isset(node, cs->mems_allowed);
task_unlock(current);
- allowed = node_isset(node, cs->mems_allowed);
mutex_unlock(&callback_mutex);
return allowed;
}