1 files changed, 20 insertions, 6 deletions

diff --git a/kernel/rcutiny.c b/kernel/rcutiny.c
index 977296dca0a4..37a5444204d2 100644
--- a/kernel/rcutiny.c
+++ b/kernel/rcutiny.c
@@ -53,7 +53,7 @@ static void __call_rcu(struct rcu_head *head,
 
 #include "rcutiny_plugin.h"
 
-static long long rcu_dynticks_nesting = DYNTICK_TASK_NESTING;
+static long long rcu_dynticks_nesting = DYNTICK_TASK_EXIT_IDLE;
 
 /* Common code for rcu_idle_enter() and rcu_irq_exit(), see kernel/rcutree.c. */
 static void rcu_idle_enter_common(long long oldval)
@@ -88,10 +88,16 @@ void rcu_idle_enter(void)
 
         local_irq_save(flags);
         oldval = rcu_dynticks_nesting;
-        rcu_dynticks_nesting = 0;
+        WARN_ON_ONCE((rcu_dynticks_nesting & DYNTICK_TASK_NEST_MASK) == 0);
+        if ((rcu_dynticks_nesting & DYNTICK_TASK_NEST_MASK) ==
+            DYNTICK_TASK_NEST_VALUE)
+                rcu_dynticks_nesting = 0;
+        else
+                rcu_dynticks_nesting  -= DYNTICK_TASK_NEST_VALUE;
         rcu_idle_enter_common(oldval);
         local_irq_restore(flags);
 }
+EXPORT_SYMBOL_GPL(rcu_idle_enter);
 
 /*
  * Exit an interrupt handler towards idle.
@@ -140,11 +146,15 @@ void rcu_idle_exit(void)
 
         local_irq_save(flags);
         oldval = rcu_dynticks_nesting;
-        WARN_ON_ONCE(oldval != 0);
-        rcu_dynticks_nesting = DYNTICK_TASK_NESTING;
+        WARN_ON_ONCE(rcu_dynticks_nesting < 0);
+        if (rcu_dynticks_nesting & DYNTICK_TASK_NEST_MASK)
+                rcu_dynticks_nesting += DYNTICK_TASK_NEST_VALUE;
+        else
+                rcu_dynticks_nesting = DYNTICK_TASK_EXIT_IDLE;
         rcu_idle_exit_common(oldval);
         local_irq_restore(flags);
 }
+EXPORT_SYMBOL_GPL(rcu_idle_exit);
 
 /*
  * Enter an interrupt handler, moving away from idle.
@@ -258,7 +268,7 @@ static void __rcu_process_callbacks(struct rcu_ctrlblk *rcp)
 
         /* If no RCU callbacks ready to invoke, just return. */
         if (&rcp->rcucblist == rcp->donetail) {
-                RCU_TRACE(trace_rcu_batch_start(rcp->name, 0, -1));
+                RCU_TRACE(trace_rcu_batch_start(rcp->name, 0, 0, -1));
                 RCU_TRACE(trace_rcu_batch_end(rcp->name, 0,
                                               ACCESS_ONCE(rcp->rcucblist),
                                               need_resched(),
@@ -269,7 +279,7 @@ static void __rcu_process_callbacks(struct rcu_ctrlblk *rcp)
 
         /* Move the ready-to-invoke callbacks to a local list. */
         local_irq_save(flags);
-        RCU_TRACE(trace_rcu_batch_start(rcp->name, 0, -1));
+        RCU_TRACE(trace_rcu_batch_start(rcp->name, 0, rcp->qlen, -1));
         list = rcp->rcucblist;
         rcp->rcucblist = *rcp->donetail;
         *rcp->donetail = NULL;
@@ -319,6 +329,10 @@ static void rcu_process_callbacks(struct softirq_action *unused)
  */
 void synchronize_sched(void)
 {
+        rcu_lockdep_assert(!lock_is_held(&rcu_bh_lock_map) &&
+                           !lock_is_held(&rcu_lock_map) &&
+                           !lock_is_held(&rcu_sched_lock_map),
+                           "Illegal synchronize_sched() in RCU read-side critical section");
         cond_resched();
 }
 EXPORT_SYMBOL_GPL(synchronize_sched);