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From:   Sasha Levin <sashal@kernel.org>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc:     Zhouyi Zhou <zhouzhouyi@gmail.com>,
        "Paul E . McKenney" <paulmck@kernel.org>,
        Sasha Levin <sashal@kernel.org>, rcu@vger.kernel.org
Subject: [PATCH AUTOSEL 5.14 037/252] rcu: Fix macro name CONFIG_TASKS_RCU_TRACE
Date:   Thu,  9 Sep 2021 07:37:31 -0400
Message-Id: <20210909114106.141462-37-sashal@kernel.org>
In-Reply-To: <20210909114106.141462-1-sashal@kernel.org>
References: <20210909114106.141462-1-sashal@kernel.org>
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From: Zhouyi Zhou <zhouzhouyi@gmail.com>

[ Upstream commit fed31a4dd3adb5455df7c704de2abb639a1dc1c0 ]

This commit fixes several typos where CONFIG_TASKS_RCU_TRACE should
instead be CONFIG_TASKS_TRACE_RCU.  Among other things, these typos
could cause CONFIG_TASKS_TRACE_RCU_READ_MB=y kernels to suffer from
memory-ordering bugs that could result in false-positive quiescent
states and too-short grace periods.

Signed-off-by: Zhouyi Zhou <zhouzhouyi@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 include/linux/rcupdate.h | 2 +-
 kernel/rcu/tree_plugin.h | 8 ++++----
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index d9680b798b21..955c82b4737c 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -167,7 +167,7 @@ void synchronize_rcu_tasks(void);
 # define synchronize_rcu_tasks synchronize_rcu
 # endif
 
-# ifdef CONFIG_TASKS_RCU_TRACE
+# ifdef CONFIG_TASKS_TRACE_RCU
 # define rcu_tasks_trace_qs(t)						\
 	do {								\
 		if (!likely(READ_ONCE((t)->trc_reader_checked)) &&	\
diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index de1dc3bb7f70..6ce104242b23 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -2982,17 +2982,17 @@ static void noinstr rcu_dynticks_task_exit(void)
 /* Turn on heavyweight RCU tasks trace readers on idle/user entry. */
 static void rcu_dynticks_task_trace_enter(void)
 {
-#ifdef CONFIG_TASKS_RCU_TRACE
+#ifdef CONFIG_TASKS_TRACE_RCU
 	if (IS_ENABLED(CONFIG_TASKS_TRACE_RCU_READ_MB))
 		current->trc_reader_special.b.need_mb = true;
-#endif /* #ifdef CONFIG_TASKS_RCU_TRACE */
+#endif /* #ifdef CONFIG_TASKS_TRACE_RCU */
 }
 
 /* Turn off heavyweight RCU tasks trace readers on idle/user exit. */
 static void rcu_dynticks_task_trace_exit(void)
 {
-#ifdef CONFIG_TASKS_RCU_TRACE
+#ifdef CONFIG_TASKS_TRACE_RCU
 	if (IS_ENABLED(CONFIG_TASKS_TRACE_RCU_READ_MB))
 		current->trc_reader_special.b.need_mb = false;
-#endif /* #ifdef CONFIG_TASKS_RCU_TRACE */
+#endif /* #ifdef CONFIG_TASKS_TRACE_RCU */
 }
-- 
2.30.2