From: "Paul E. McKenney" <paulmck@xxxxxxxxxx> The rcu_state structure's ->gp_start field is read locklessly, so this commit adds the WRITE_ONCE() to an update in order to provide proper documentation and READ_ONCE()/WRITE_ONCE() pairing. This data race was reported by KCSAN. Not appropriate for backporting due to failure being unlikely. Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxx> --- kernel/rcu/tree_stall.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/rcu/tree_stall.h b/kernel/rcu/tree_stall.h index 3275f27..56df88e 100644 --- a/kernel/rcu/tree_stall.h +++ b/kernel/rcu/tree_stall.h @@ -102,7 +102,7 @@ static void record_gp_stall_check_time(void) unsigned long j = jiffies; unsigned long j1; - rcu_state.gp_start = j; + WRITE_ONCE(rcu_state.gp_start, j); j1 = rcu_jiffies_till_stall_check(); /* Record ->gp_start before ->jiffies_stall. */ smp_store_release(&rcu_state.jiffies_stall, j + j1); /* ^^^ */ -- 2.9.5
