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Diffstat (limited to 'kernel/rcu/tree_nocb.h')
-rw-r--r--kernel/rcu/tree_nocb.h13
1 files changed, 12 insertions, 1 deletions
diff --git a/kernel/rcu/tree_nocb.h b/kernel/rcu/tree_nocb.h
index 16865475120b..2605dd234a13 100644
--- a/kernel/rcu/tree_nocb.h
+++ b/kernel/rcu/tree_nocb.h
@@ -891,7 +891,18 @@ static void nocb_cb_wait(struct rcu_data *rdp)
swait_event_interruptible_exclusive(rdp->nocb_cb_wq,
nocb_cb_wait_cond(rdp));
if (kthread_should_park()) {
- kthread_parkme();
+ /*
+ * kthread_park() must be preceded by an rcu_barrier().
+ * But yet another rcu_barrier() might have sneaked in between
+ * the barrier callback execution and the callbacks counter
+ * decrement.
+ */
+ if (rdp->nocb_cb_sleep) {
+ rcu_nocb_lock_irqsave(rdp, flags);
+ WARN_ON_ONCE(rcu_segcblist_n_cbs(&rdp->cblist));
+ rcu_nocb_unlock_irqrestore(rdp, flags);
+ kthread_parkme();
+ }
} else if (READ_ONCE(rdp->nocb_cb_sleep)) {
WARN_ON(signal_pending(current));
trace_rcu_nocb_wake(rcu_state.name, rdp->cpu, TPS("WokeEmpty"));