rcu: Protect rcu_boost() lockless accesses with ACCESS_ONCE()



This commit prevents random compiler optimizations by applying
ACCESS_ONCE() to lockless accesses.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

parent 734d1680

kernel/rcu/tree_plugin.h

+2 −1

Original line number	Diff line number	Diff line
		@@ -1127,7 +1127,8 @@ static int rcu_boost(struct rcu_node *rnp)
		struct task_struct *t;
		struct list_head *tb;

		if (rnp->exp_tasks == NULL && rnp->boost_tasks == NULL)
		if (ACCESS_ONCE(rnp->exp_tasks) == NULL &&
		ACCESS_ONCE(rnp->boost_tasks) == NULL)
		return 0; /* Nothing left to boost. */

		raw_spin_lock_irqsave(&rnp->lock, flags);