linux-kernel - [PATCH AUTOSEL 5.9 24/33] cpuidle: tegra: Annotate tegra_pm_set_cpu_in_lp2() with RCU

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Message-Id: <20201125153550.810101-24-sashal@kernel.org>
Date:   Wed, 25 Nov 2020 10:35:41 -0500
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Dmitry Osipenko <digetx@...il.com>,
        Peter Geis <pgwipeout@...il.com>,
        "Rafael J . Wysocki" <rafael.j.wysocki@...el.com>,
        Sasha Levin <sashal@...nel.org>, linux-pm@...r.kernel.org,
        linux-tegra@...r.kernel.org
Subject: [PATCH AUTOSEL 5.9 24/33] cpuidle: tegra: Annotate tegra_pm_set_cpu_in_lp2() with RCU_NONIDLE

From: Dmitry Osipenko <digetx@...il.com>

[ Upstream commit c39de538a06e76d89b7e598a71e16688009cd56c ]

Annotate tegra_pm_set[clear]_cpu_in_lp2() with RCU_NONIDLE in order to
fix lockdep warning about suspicious RCU usage of a spinlock during late
idling phase.

 WARNING: suspicious RCU usage
 ...
 include/trace/events/lock.h:13 suspicious rcu_dereference_check() usage!
 ...
  (dump_stack) from (lock_acquire)
  (lock_acquire) from (_raw_spin_lock)
  (_raw_spin_lock) from (tegra_pm_set_cpu_in_lp2)
  (tegra_pm_set_cpu_in_lp2) from (tegra_cpuidle_enter)
  (tegra_cpuidle_enter) from (cpuidle_enter_state)
  (cpuidle_enter_state) from (cpuidle_enter_state_coupled)
  (cpuidle_enter_state_coupled) from (cpuidle_enter)
  (cpuidle_enter) from (do_idle)
 ...

Tested-by: Peter Geis <pgwipeout@...il.com>
Reported-by: Peter Geis <pgwipeout@...il.com>
Signed-off-by: Dmitry Osipenko <digetx@...il.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/cpuidle/cpuidle-tegra.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/cpuidle/cpuidle-tegra.c b/drivers/cpuidle/cpuidle-tegra.c
index e8956706a2917..191966dc8d023 100644
--- a/drivers/cpuidle/cpuidle-tegra.c
+++ b/drivers/cpuidle/cpuidle-tegra.c
@@ -189,7 +189,7 @@ static int tegra_cpuidle_state_enter(struct cpuidle_device *dev,
 	}
 
 	local_fiq_disable();
-	tegra_pm_set_cpu_in_lp2();
+	RCU_NONIDLE(tegra_pm_set_cpu_in_lp2());
 	cpu_pm_enter();
 
 	switch (index) {
@@ -207,7 +207,7 @@ static int tegra_cpuidle_state_enter(struct cpuidle_device *dev,
 	}
 
 	cpu_pm_exit();
-	tegra_pm_clear_cpu_in_lp2();
+	RCU_NONIDLE(tegra_pm_clear_cpu_in_lp2());
 	local_fiq_enable();
 
 	return err ?: index;
-- 
2.27.0