rcu: Apply ACCESS_ONCE() to rcu_boost() return value
Both TINY_RCU's and TREE_RCU's implementations of rcu_boost() access
the ->boost_tasks and ->exp_tasks fields without preventing concurrent
changes to these fields. This commit therefore applies ACCESS_ONCE in
order to prevent compiler mischief.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
diff --git a/kernel/rcutiny_plugin.h b/kernel/rcutiny_plugin.h
index dfa97cb..9cb1ae4 100644
--- a/kernel/rcutiny_plugin.h
+++ b/kernel/rcutiny_plugin.h
@@ -312,8 +312,8 @@
rt_mutex_lock(&mtx);
rt_mutex_unlock(&mtx); /* Keep lockdep happy. */
- return rcu_preempt_ctrlblk.boost_tasks != NULL ||
- rcu_preempt_ctrlblk.exp_tasks != NULL;
+ return ACCESS_ONCE(rcu_preempt_ctrlblk.boost_tasks) != NULL ||
+ ACCESS_ONCE(rcu_preempt_ctrlblk.exp_tasks) != NULL;
}
/*