From: Daniel Fu <danifu@nvidia.com>
Date: Fri, 30 Aug 2013 11:48:22 +0000 (+0800)
Subject: cpuidle: Check the result of cpuidle_get_driver() against NULL
X-Git-Tag: v3.12-rc1~35^2~3^2
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=3b9c10e98021e1f92e6f8c7ce1778b86ba68db10;p=profile%2Fivi%2Fkernel-x86-ivi.git

cpuidle: Check the result of cpuidle_get_driver() against NULL

If the current CPU has no cpuidle driver, drv will be NULL in
cpuidle_driver_ref().  Check if that is the case before trying
to bump up the driver's refcount to prevent the kernel from
crashing.

[rjw: Subject and changelog]
Signed-off-by: Daniel Fu <danifu@nvidia.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---

diff --git a/drivers/cpuidle/driver.c b/drivers/cpuidle/driver.c
index 3ac499d..6e11701 100644
--- a/drivers/cpuidle/driver.c
+++ b/drivers/cpuidle/driver.c
@@ -331,7 +331,8 @@ struct cpuidle_driver *cpuidle_driver_ref(void)
 	spin_lock(&cpuidle_driver_lock);
 
 	drv = cpuidle_get_driver();
-	drv->refcnt++;
+	if (drv)
+		drv->refcnt++;
 
 	spin_unlock(&cpuidle_driver_lock);
 	return drv;