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Message-Id: <20211202001040.3126390-4-paulmck@kernel.org>
Date: Wed, 1 Dec 2021 16:10:37 -0800
From: "Paul E. McKenney" <paulmck@...nel.org>
To: rcu@...r.kernel.org
Cc: linux-kernel@...r.kernel.org, kernel-team@...com, mingo@...nel.org,
jiangshanlai@...il.com, akpm@...ux-foundation.org,
mathieu.desnoyers@...icios.com, josh@...htriplett.org,
tglx@...utronix.de, peterz@...radead.org, rostedt@...dmis.org,
dhowells@...hat.com, edumazet@...gle.com, fweisbec@...il.com,
oleg@...hat.com, joel@...lfernandes.org,
"Paul E. McKenney" <paulmck@...nel.org>
Subject: [PATCH rcu 4/7] rcu: Mark sync_sched_exp_online_cleanup() ->cpu_no_qs.b.exp load
The sync_sched_exp_online_cleanup() is called from rcutree_online_cpu(),
which can be invoked with interrupts enabled. This means that
the ->cpu_no_qs.b.exp field is subject to data races from the
rcu_exp_handler() IPI handler, so this commit marks the load from
that field.
Signed-off-by: Paul E. McKenney <paulmck@...nel.org>
---
kernel/rcu/tree_exp.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/rcu/tree_exp.h b/kernel/rcu/tree_exp.h
index fc2ee326a6f73..12f1a18d7b6d6 100644
--- a/kernel/rcu/tree_exp.h
+++ b/kernel/rcu/tree_exp.h
@@ -759,7 +759,7 @@ static void sync_sched_exp_online_cleanup(int cpu)
my_cpu = get_cpu();
/* Quiescent state either not needed or already requested, leave. */
if (!(READ_ONCE(rnp->expmask) & rdp->grpmask) ||
- rdp->cpu_no_qs.b.exp) {
+ READ_ONCE(rdp->cpu_no_qs.b.exp)) {
put_cpu();
return;
}
--
2.31.1.189.g2e36527f23
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