Commit 39f91504 authored Dec 22, 2019 by Paul E. McKenney

srcu: Fix process_srcu()/srcu_batches_completed() datarace



The srcu_struct structure's ->srcu_idx field is accessed locklessly,
so reads must use READ_ONCE().  This commit therefore adds the needed
READ_ONCE() invocation where it was missed.

This data race was reported by KCSAN.  Not appropriate for backporting
due to failure being unlikely.

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

parent 8c9e0cb3

kernel/rcu/srcutree.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -1079,7 +1079,7 @@ EXPORT_SYMBOL_GPL(srcu_barrier);
		*/
		unsigned long srcu_batches_completed(struct srcu_struct *ssp)
		{
		return ssp->srcu_idx;
		return READ_ONCE(ssp->srcu_idx);
		}
		EXPORT_SYMBOL_GPL(srcu_batches_completed);