Commit d295ad34 authored by Waiman Long's avatar Waiman Long Committed by Rafael J. Wysocki
Browse files

intel_idle: Fix false positive RCU splats due to incorrect hardirqs state 



Commit 32d4fd57 ("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: 32d4fd57 ("cpuidle,intel_idle: Fix CPUIDLE_FLAG_IRQ_ENABLE")
Signed-off-by: default avatarWaiman Long <longman@redhat.com>
Cc: 5.16+ <stable@vger.kernel.org> # 5.16+
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent e0dccc3b

drivers/idle/intel_idle.c

+7 −1
Original line number Diff line number Diff line
@@ -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;

}