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

2 files changed, 10 insertions, 6 deletions

diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index ff476515f716..581abf848566 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -230,12 +230,11 @@ void __wait_rcu_gp(bool checktiny, int n, call_rcu_func_t *crcu_array,
                    struct rcu_synchronize *rs_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); \
+do {                                                                    \
+        call_rcu_func_t __crcu_array[] = { __VA_ARGS__ };               \
+        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__)
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 9f75f25cc5d9..775d36cc0050 100644
--- a/kernel/rcu/tree.c
+++ b/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");
 }
 
 /*