Commit bfeebe24 authored Jan 03, 2020 by Paul E. McKenney

rcu: Add READ_ONCE() to rcu_segcblist ->tails[]



The rcu_segcblist structure's ->tails[] array entries are read
locklessly, so this commit adds the READ_ONCE() to a load in order to
avoid destructive compiler optimizations.

This data race was reported by KCSAN.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

parent 0050c7b2

kernel/rcu/rcu_segcblist.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -182,7 +182,7 @@ void rcu_segcblist_offload(struct rcu_segcblist *rsclp)
		bool rcu_segcblist_ready_cbs(struct rcu_segcblist *rsclp)
		{
		return rcu_segcblist_is_enabled(rsclp) &&
		&rsclp->head != rsclp->tails[RCU_DONE_TAIL];
		&rsclp->head != READ_ONCE(rsclp->tails[RCU_DONE_TAIL]);
		}

		/*

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