1 files changed, 19 insertions, 0 deletions

diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index f409529ff35..146d37d3177 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -226,6 +226,15 @@ static inline void destroy_rcu_head_on_stack(struct rcu_head *head)
 }
 #endif  /* #else !CONFIG_DEBUG_OBJECTS_RCU_HEAD */
 
+#if defined(CONFIG_HOTPLUG_CPU) && defined(CONFIG_PROVE_RCU)
+bool rcu_lockdep_current_cpu_online(void);
+#else /* #if defined(CONFIG_HOTPLUG_CPU) && defined(CONFIG_PROVE_RCU) */
+static inline bool rcu_lockdep_current_cpu_online(void)
+{
+        return 1;
+}
+#endif /* #else #if defined(CONFIG_HOTPLUG_CPU) && defined(CONFIG_PROVE_RCU) */
+
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 
 #ifdef CONFIG_PROVE_RCU
@@ -270,6 +279,9 @@ extern int debug_lockdep_rcu_enabled(void);
  * occur in the same context, for example, it is illegal to invoke
  * rcu_read_unlock() in process context if the matching rcu_read_lock()
  * was invoked from within an irq handler.
+ *
+ * Note that rcu_read_lock() is disallowed if the CPU is either idle or
+ * offline from an RCU perspective, so check for those as well.
  */
 static inline int rcu_read_lock_held(void)
 {
@@ -277,6 +289,8 @@ static inline int rcu_read_lock_held(void)
                 return 1;
         if (rcu_is_cpu_idle())
                 return 0;
+        if (!rcu_lockdep_current_cpu_online())
+                return 0;
         return lock_is_held(&rcu_lock_map);
 }
 
@@ -313,6 +327,9 @@ extern int rcu_read_lock_bh_held(void);
  * notice an extended quiescent state to other CPUs that started a grace
  * period. Otherwise we would delay any grace period as long as we run in
  * the idle task.
+ *
+ * Similarly, we avoid claiming an SRCU read lock held if the current
+ * CPU is offline.
  */
 #ifdef CONFIG_PREEMPT_COUNT
 static inline int rcu_read_lock_sched_held(void)
@@ -323,6 +340,8 @@ static inline int rcu_read_lock_sched_held(void)
                 return 1;
         if (rcu_is_cpu_idle())
                 return 0;
+        if (!rcu_lockdep_current_cpu_online())
+                return 0;
         if (debug_locks)
                 lockdep_opinion = lock_is_held(&rcu_sched_lock_map);
         return lockdep_opinion || preempt_count() != 0 || irqs_disabled();