Merge branch 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull RCU fixes from Ingo Molnar:
 "Two RCU fixes:

   - work around bug with recent GCC versions.

   - fix false positive lockdep splat"

* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  rcu: Suppress lockdep false positive for rcp->exp_funnel_mutex
  rcu: Change _wait_rcu_gp() to work around GCC bug 67055

include/linux/rcupdate.h

@@ -232,10 +232,9 @@ void __wait_rcu_gp(bool checktiny, int n, call_rcu_func_t *crcu_array,
 #define _wait_rcu_gp(checktiny, ...) \
 do {									\
 	call_rcu_func_t __crcu_array[] = { __VA_ARGS__ };		\
-	const int __n = ARRAY_SIZE(__crcu_array); \
-	struct rcu_synchronize __rs_array[__n]; \
-	\
-	__wait_rcu_gp(checktiny, __n, __crcu_array, __rs_array); \
+	struct rcu_synchronize __rs_array[ARRAY_SIZE(__crcu_array)];	\
+	__wait_rcu_gp(checktiny, ARRAY_SIZE(__crcu_array),		\
+			__crcu_array, __rs_array);			\
 } while (0)
 
 #define wait_rcu_gp(...) _wait_rcu_gp(false, __VA_ARGS__)

kernel/rcu/tree.c

@@ -3868,6 +3868,7 @@ static void rcu_init_new_rnp(struct rcu_node *rnp_leaf)
 static void __init
 rcu_boot_init_percpu_data(int cpu, struct rcu_state *rsp)
 {
+	static struct lock_class_key rcu_exp_sched_rdp_class;
 	unsigned long flags;
 	struct rcu_data *rdp = per_cpu_ptr(rsp->rda, cpu);
 	struct rcu_node *rnp = rcu_get_root(rsp);
@@ -3883,6 +3884,10 @@ rcu_boot_init_percpu_data(int cpu, struct rcu_state *rsp)
 	mutex_init(&rdp->exp_funnel_mutex);
 	rcu_boot_init_nocb_percpu_data(rdp);
 	raw_spin_unlock_irqrestore(&rnp->lock, flags);
+	if (rsp == &rcu_sched_state)
+		lockdep_set_class_and_name(&rdp->exp_funnel_mutex,
+					   &rcu_exp_sched_rdp_class,
+					   "rcu_data_exp_sched");
 }
 
 /*