1 files changed, 41 insertions, 0 deletions

diff --git a/kernel/rcupdate.c b/kernel/rcupdate.c
index f1125c1a6321..49d808e833b0 100644
--- a/kernel/rcupdate.c
+++ b/kernel/rcupdate.c
@@ -45,6 +45,7 @@
 #include <linux/mutex.h>
 #include <linux/module.h>
 #include <linux/kernel_stat.h>
+#include <linux/hardirq.h>
 
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 static struct lock_class_key rcu_lock_key;
@@ -66,6 +67,35 @@ EXPORT_SYMBOL_GPL(rcu_sched_lock_map);
 int rcu_scheduler_active __read_mostly;
 EXPORT_SYMBOL_GPL(rcu_scheduler_active);
 
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+
+int debug_lockdep_rcu_enabled(void)
+{
+        return rcu_scheduler_active && debug_locks &&
+               current->lockdep_recursion == 0;
+}
+EXPORT_SYMBOL_GPL(debug_lockdep_rcu_enabled);
+
+/**
+ * rcu_read_lock_bh_held - might we be in RCU-bh read-side critical section?
+ *
+ * Check for bottom half being disabled, which covers both the
+ * CONFIG_PROVE_RCU and not cases.  Note that if someone uses
+ * rcu_read_lock_bh(), but then later enables BH, lockdep (if enabled)
+ * will show the situation.
+ *
+ * Check debug_lockdep_rcu_enabled() to prevent false positives during boot.
+ */
+int rcu_read_lock_bh_held(void)
+{
+        if (!debug_lockdep_rcu_enabled())
+                return 1;
+        return in_softirq();
+}
+EXPORT_SYMBOL_GPL(rcu_read_lock_bh_held);
+
+#endif /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */
+
 /*
  * This function is invoked towards the end of the scheduler's initialization
  * process.  Before this is called, the idle task might contain
@@ -92,3 +122,14 @@ void wakeme_after_rcu(struct rcu_head  *head)
         rcu = container_of(head, struct rcu_synchronize, head);
         complete(&rcu->completion);
 }
+
+#ifdef CONFIG_PROVE_RCU
+/*
+ * wrapper function to avoid #include problems.
+ */
+int rcu_my_thread_group_empty(void)
+{
+        return thread_group_empty(current);
+}
+EXPORT_SYMBOL_GPL(rcu_my_thread_group_empty);
+#endif /* #ifdef CONFIG_PROVE_RCU */