linux-kernel - [PATCH] cpuidle: fix broadcast control when broadcast can not be entered

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Message-Id: <20170901042956.29594-1-npiggin@gmail.com>
Date:   Fri,  1 Sep 2017 14:29:56 +1000
From:   Nicholas Piggin <npiggin@...il.com>
To:     "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Daniel Lezcano <daniel.lezcano@...aro.org>
Cc:     Nicholas Piggin <npiggin@...il.com>, linux-pm@...r.kernel.org,
        linux-kernel@...r.kernel.org, Thomas Gleixner <tglx@...utronix.de>
Subject: [PATCH] cpuidle: fix broadcast control when broadcast can not be entered

When failing to enter broadcast timer mode for an idle state that
requires it, a new state is selected that does not require broadcast,
but the broadcast variable remains set. This causes
tick_broadcast_exit to be called despite not having entered broadcast
mode.

This causes the WARN_ON_ONCE(!irqs_disabled()) to trigger in some
cases. It does not appear to cause problems for code today, but seems
to violate the interface so should be fixed.

Signed-off-by: Nicholas Piggin <npiggin@...il.com>
---
 drivers/cpuidle/cpuidle.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
index 60bb64f4329d..4453e27f855e 100644
--- a/drivers/cpuidle/cpuidle.c
+++ b/drivers/cpuidle/cpuidle.c
@@ -208,6 +208,7 @@ int cpuidle_enter_state(struct cpuidle_device *dev, struct cpuidle_driver *drv,
 			return -EBUSY;
 		}
 		target_state = &drv->states[index];
+		broadcast = false;
 	}

 	/* Take note of the planned idle state. */
-- 
2.13.3