[PATCH AUTOSEL 5.10 021/176] rcu: Fix macro name CONFIG_TASKS_RCU_TRACE

Sasha Levin
2021-09-09T12:39:26Z

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 0d7013da818c..095b3b39bd03 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -163,7 +163,7 @@ 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 7d4f78bf4057..8ea96a72c48e 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -2590,17 +2590,17 @@ 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