From b68c6146512d92f6d570d26e1873497ade2cc4cb Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Fri, 3 Jan 2020 16:36:59 -0800 Subject: srcu: Add data_race() to ->srcu_lock_count and ->srcu_unlock_count arrays The srcu_data structure's ->srcu_lock_count and ->srcu_unlock_count arrays are read and written locklessly, so this commit adds the data_race() to the diagnostic-print loads from these arrays in order mark them as known and approved data-racy accesses. This data race was reported by KCSAN. Not appropriate for backporting due to failure being unlikely and due to this being used only by rcutorture. Signed-off-by: Paul E. McKenney --- kernel/rcu/srcutree.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'kernel/rcu/srcutree.c') diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c index ba2b751e9168..6d3ef700fb0e 100644 --- a/kernel/rcu/srcutree.c +++ b/kernel/rcu/srcutree.c @@ -1281,8 +1281,8 @@ void srcu_torture_stats_print(struct srcu_struct *ssp, char *tt, char *tf) struct srcu_data *sdp; sdp = per_cpu_ptr(ssp->sda, cpu); - u0 = sdp->srcu_unlock_count[!idx]; - u1 = sdp->srcu_unlock_count[idx]; + u0 = data_race(sdp->srcu_unlock_count[!idx]); + u1 = data_race(sdp->srcu_unlock_count[idx]); /* * Make sure that a lock is always counted if the corresponding @@ -1290,8 +1290,8 @@ void srcu_torture_stats_print(struct srcu_struct *ssp, char *tt, char *tf) */ smp_rmb(); - l0 = sdp->srcu_lock_count[!idx]; - l1 = sdp->srcu_lock_count[idx]; + l0 = data_race(sdp->srcu_lock_count[!idx]); + l1 = data_race(sdp->srcu_lock_count[idx]); c0 = l0 - u0; c1 = l1 - u1; -- cgit v1.2.3