From d295ad34f236c3518634fb6403d4c0160456e470 Mon Sep 17 00:00:00 2001 From: Waiman Long Date: Sat, 23 Jul 2022 15:59:32 -0400 Subject: [PATCH] intel_idle: Fix false positive RCU splats due to incorrect hardirqs state Commit 32d4fd5751ea ("cpuidle,intel_idle: Fix CPUIDLE_FLAG_IRQ_ENABLE") uses raw_local_irq_enable/local_irq_disable() around call to __intel_idle() in intel_idle_irq(). With interrupt enabled, timer tick interrupt can happen and a subsequently call to __do_softirq() may change the lockdep hardirqs state of a debug kernel back to 'on'. This will result in a mismatch between the cpu hardirqs state (off) and the lockdep hardirqs state (on) causing a number of false positive "WARNING: suspicious RCU usage" splats. Fix that by using local_irq_disable() to disable interrupt in intel_idle_irq(). Fixes: 32d4fd5751ea ("cpuidle,intel_idle: Fix CPUIDLE_FLAG_IRQ_ENABLE") Signed-off-by: Waiman Long Cc: 5.16+ # 5.16+ Signed-off-by: Rafael J. Wysocki --- drivers/idle/intel_idle.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/drivers/idle/intel_idle.c b/drivers/idle/intel_idle.c index f5c6802aa6c3..907700d1e78e 100644 --- a/drivers/idle/intel_idle.c +++ b/drivers/idle/intel_idle.c @@ -162,7 +162,13 @@ static __cpuidle int intel_idle_irq(struct cpuidle_device *dev, raw_local_irq_enable(); ret = __intel_idle(dev, drv, index); - raw_local_irq_disable(); + + /* + * The lockdep hardirqs state may be changed to 'on' with timer + * tick interrupt followed by __do_softirq(). Use local_irq_disable() + * to keep the hardirqs state correct. + */ + local_irq_disable(); return ret; }