2 files changed, 9 insertions, 2 deletions

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 496770a96487..76676a407e4a 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1254,6 +1254,9 @@ struct task_struct {
 #ifdef CONFIG_PREEMPT_RCU
         int rcu_read_lock_nesting;
         char rcu_read_unlock_special;
+#if defined(CONFIG_RCU_BOOST) && defined(CONFIG_TREE_PREEMPT_RCU)
+        int rcu_boosted;
+#endif /* #if defined(CONFIG_RCU_BOOST) && defined(CONFIG_TREE_PREEMPT_RCU) */
         struct list_head rcu_node_entry;
 #endif /* #ifdef CONFIG_PREEMPT_RCU */
 #ifdef CONFIG_TREE_PREEMPT_RCU
diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h
index 6abef3cfcbc1..3a0ae0355222 100644
--- a/kernel/rcutree_plugin.h
+++ b/kernel/rcutree_plugin.h
@@ -342,6 +342,11 @@ static void rcu_read_unlock_special(struct task_struct *t)
 #ifdef CONFIG_RCU_BOOST
                 if (&t->rcu_node_entry == rnp->boost_tasks)
                         rnp->boost_tasks = np;
+                /* Snapshot and clear ->rcu_boosted with rcu_node lock held. */
+                if (t->rcu_boosted) {
+                        special |= RCU_READ_UNLOCK_BOOSTED;
+                        t->rcu_boosted = 0;
+                }
 #endif /* #ifdef CONFIG_RCU_BOOST */
                 t->rcu_blocked_node = NULL;
 
@@ -358,7 +363,6 @@ static void rcu_read_unlock_special(struct task_struct *t)
 #ifdef CONFIG_RCU_BOOST
                 /* Unboost if we were boosted. */
                 if (special & RCU_READ_UNLOCK_BOOSTED) {
-                        t->rcu_read_unlock_special &= ~RCU_READ_UNLOCK_BOOSTED;
                         rt_mutex_unlock(t->rcu_boost_mutex);
                         t->rcu_boost_mutex = NULL;
                 }
@@ -1176,7 +1180,7 @@ static int rcu_boost(struct rcu_node *rnp)
         t = container_of(tb, struct task_struct, rcu_node_entry);
         rt_mutex_init_proxy_locked(&mtx, t);
         t->rcu_boost_mutex = &mtx;
-        t->rcu_read_unlock_special |= RCU_READ_UNLOCK_BOOSTED;
+        t->rcu_boosted = 1;
         raw_spin_unlock_irqrestore(&rnp->lock, flags);
         rt_mutex_lock(&mtx);  /* Side effect: boosts task t's priority. */
         rt_mutex_unlock(&mtx);  /* Keep lockdep happy. */