From: "Paul E. McKenney" <paulmck@kernel.org>
To: rcu@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, kernel-team@fb.com,
rostedt@goodmis.org, "Paul E. McKenney" <paulmck@kernel.org>
Subject: [PATCH rcu 2/3] rcu: Mark ->expmask access in synchronize_rcu_expedited_wait()
Date: Fri, 4 Feb 2022 14:55:06 -0800 [thread overview]
Message-ID: <20220204225507.4193113-2-paulmck@kernel.org> (raw)
In-Reply-To: <20220204225409.GA4193020@paulmck-ThinkPad-P17-Gen-1>
This commit adds a READ_ONCE() to an access to the rcu_node structure's
->expmask field to prevent compiler mischief. Detected by KCSAN.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
kernel/rcu/tree_exp.h | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/kernel/rcu/tree_exp.h b/kernel/rcu/tree_exp.h
index 1568c8ef185b2..60197ea24ceb9 100644
--- a/kernel/rcu/tree_exp.h
+++ b/kernel/rcu/tree_exp.h
@@ -502,7 +502,8 @@ static void synchronize_rcu_expedited_wait(void)
if (synchronize_rcu_expedited_wait_once(1))
return;
rcu_for_each_leaf_node(rnp) {
- for_each_leaf_node_cpu_mask(rnp, cpu, rnp->expmask) {
+ mask = READ_ONCE(rnp->expmask);
+ for_each_leaf_node_cpu_mask(rnp, cpu, mask) {
rdp = per_cpu_ptr(&rcu_data, cpu);
if (rdp->rcu_forced_tick_exp)
continue;
--
2.31.1.189.g2e36527f23
next prev parent reply other threads:[~2022-02-04 22:55 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-04 22:54 [PATCH rcu 0/3] Expedited-grace-period updates for v5.18 Paul E. McKenney
2022-02-04 22:55 ` [PATCH rcu 1/3] rcu/exp: Fix check for idle context in rcu_exp_handler Paul E. McKenney
2022-02-04 22:55 ` Paul E. McKenney [this message]
2022-02-04 22:55 ` [PATCH rcu 3/3] rcu: Allow expedited RCU grace periods on incoming CPUs Paul E. McKenney
2022-02-08 18:56 ` Tejun Heo
2022-02-09 18:23 ` Mukesh Ojha
2022-02-09 22:06 ` Paul E. McKenney
2022-02-11 18:44 ` Mukesh Ojha
2022-02-11 22:14 ` Paul E. McKenney
2022-02-12 8:47 ` Mukesh Ojha
2022-02-12 11:28 ` Neeraj Upadhyay
2022-02-12 13:56 ` Mukesh Ojha
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