From 3735d524da64b70b41c764359da36f88aded3610 Mon Sep 17 00:00:00 2001
From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Date: Thu, 16 Aug 2012 22:06:55 +0200
Subject: intel_idle: Check cpu_idle_get_driver() for NULL before dereferencing
 it.

If the machine is booted without any cpu_idle driver set
(b/c disable_cpuidle() has been called) we should follow
other users of cpu_idle API and check the return value
for NULL before using it.

Reported-and-tested-by: Mark van Dijk <mark@internecto.net>
Suggested-by: Jan Beulich <JBeulich@suse.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

diff --git a/drivers/idle/intel_idle.c b/drivers/idle/intel_idle.c
index f559088..e872617 100644
--- a/drivers/idle/intel_idle.c
+++ b/drivers/idle/intel_idle.c
@@ -606,8 +606,9 @@ static int __init intel_idle_init(void)
 	intel_idle_cpuidle_driver_init();
 	retval = cpuidle_register_driver(&intel_idle_driver);
 	if (retval) {
+		struct cpuidle_driver *drv = cpuidle_get_driver();
 		printk(KERN_DEBUG PREFIX "intel_idle yielding to %s",
-			cpuidle_get_driver()->name);
+			drv ? drv->name : "none");
 		return retval;
 	}
 
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