From: "Paul E. McKenney" <paulmck@kernel.org>
To: rcu@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, kernel-team@fb.com,
mingo@kernel.org, jiangshanlai@gmail.com,
akpm@linux-foundation.org, mathieu.desnoyers@efficios.com,
josh@joshtriplett.org, tglx@linutronix.de, peterz@infradead.org,
rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com,
fweisbec@gmail.com, oleg@redhat.com, joel@joelfernandes.org,
"Paul E. McKenney" <paulmck@kernel.org>
Subject: [PATCH rcu 4/7] rcu: Mark sync_sched_exp_online_cleanup() ->cpu_no_qs.b.exp load
Date: Wed, 1 Dec 2021 16:10:37 -0800 [thread overview]
Message-ID: <20211202001040.3126390-4-paulmck@kernel.org> (raw)
In-Reply-To: <20211202001016.GA3126278@paulmck-ThinkPad-P17-Gen-1>
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@kernel.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
next prev parent reply other threads:[~2021-12-02 0:12 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-02 0:10 [PATCH rcu 0/7] Expedited-grace-period updates for v5.17 Paul E. McKenney
2021-12-02 0:10 ` [PATCH rcu 1/7] rcu: Ignore rdp.cpu_no_qs.b.exp on preemptible RCU's rcu_qs() Paul E. McKenney
2021-12-02 0:10 ` [PATCH rcu 2/7] rcu: Move rcu_data.cpu_no_qs.b.exp reset to rcu_export_exp_rdp() Paul E. McKenney
2021-12-02 0:10 ` [PATCH rcu 3/7] rcu: Remove rcu_data.exp_deferred_qs and convert to rcu_data.cpu no_qs.b.exp Paul E. McKenney
2021-12-02 0:10 ` Paul E. McKenney [this message]
2021-12-02 0:10 ` [PATCH rcu 5/7] rcu: Prevent expedited GP from enabling tick on offline CPU Paul E. McKenney
2021-12-02 0:10 ` [PATCH rcu 6/7] rcu: Make idle entry report expedited quiescent states Paul E. McKenney
2021-12-02 0:10 ` [PATCH rcu 7/7] rcu/exp: Mark current CPU as exp-QS in IPI loop second pass Paul E. McKenney
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