linux-kernel - [PATCH 4.4 72/78] cpuidle: fix broadcast control when broadcast can not be entered

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Date:   Fri, 22 Dec 2017 09:46:53 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Nicholas Piggin <npiggin@...il.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        "Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
        Sasha Levin <alexander.levin@...izon.com>
Subject: [PATCH 4.4 72/78] cpuidle: fix broadcast control when broadcast can not be entered

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Nicholas Piggin <npiggin@...il.com>

[ Upstream commit f187851b9b4a76952b1158b86434563dd2031103 ]

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>
Reviewed-by: Thomas Gleixner <tglx@...utronix.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
Signed-off-by: Sasha Levin <alexander.levin@...izon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 drivers/cpuidle/cpuidle.c |    1 +
 1 file changed, 1 insertion(+)

--- a/drivers/cpuidle/cpuidle.c
+++ b/drivers/cpuidle/cpuidle.c
@@ -189,6 +189,7 @@ int cpuidle_enter_state(struct cpuidle_d
 			return -EBUSY;
 		}
 		target_state = &drv->states[index];
+		broadcast = false;
 	}

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