1 files changed, 5 insertions, 1 deletions

diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index 6abb03dff5c0..b023e5407111 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -779,8 +779,10 @@ static void rcu_report_exp_rnp(struct rcu_state *rsp, struct rcu_node *rnp,
                 }
                 if (rnp->parent == NULL) {
                         raw_spin_unlock_irqrestore(&rnp->lock, flags);
-                        if (wake)
+                        if (wake) {
+                                smp_mb(); /* EGP done before wake_up(). */
                                 wake_up(&sync_rcu_preempt_exp_wq);
+                        }
                         break;
                 }
                 mask = rnp->grpmask;
@@ -1852,6 +1854,7 @@ static int rcu_oom_notify(struct notifier_block *self,
 
         /* Wait for callbacks from earlier instance to complete. */
         wait_event(oom_callback_wq, atomic_read(&oom_callback_count) == 0);
+        smp_mb(); /* Ensure callback reuse happens after callback invocation. */
 
         /*
          * Prevent premature wakeup: ensure that all increments happen
@@ -2250,6 +2253,7 @@ static int rcu_nocb_kthread(void *arg)
                         trace_rcu_nocb_wake(rdp->rsp->name, rdp->cpu,
                                             TPS("Sleep"));
                         wait_event_interruptible(rdp->nocb_wq, rdp->nocb_head);
+                        /* Memory barrier provide by xchg() below. */
                 } else if (firsttime) {
                         firsttime = 0;
                         trace_rcu_nocb_wake(rdp->rsp->name, rdp->cpu,