1 files changed, 9 insertions, 4 deletions

diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index 681a5d58d40d..e04c2da9dadb 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -647,10 +647,15 @@ void cpuset_update_task_memory_state()
         struct task_struct *tsk = current;
         struct cpuset *cs;
 
-        rcu_read_lock();
-        cs = rcu_dereference(tsk->cpuset);
-        my_cpusets_mem_gen = cs->mems_generation;
-        rcu_read_unlock();
+        if (tsk->cpuset == &top_cpuset) {
+                /* Don't need rcu for top_cpuset.  It's never freed. */
+                my_cpusets_mem_gen = top_cpuset.mems_generation;
+        } else {
+                rcu_read_lock();
+                cs = rcu_dereference(tsk->cpuset);
+                my_cpusets_mem_gen = cs->mems_generation;
+                rcu_read_unlock();
+        }
 
         if (my_cpusets_mem_gen != tsk->cpuset_mems_generation) {
                 down(&callback_sem);