[PATCH 3.11 38/46] cpuidle: Check the result of cpuidle_get_driver() against NULL

From: Luis Henriques
Date: Wed Apr 16 2014 - 06:35:14 EST


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

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

From: Daniel Fu <danifu@xxxxxxxxxx>

commit 3b9c10e98021e1f92e6f8c7ce1778b86ba68db10 upstream.

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@xxxxxxxxxx>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Cc: Mark Brown <broonie@xxxxxxxxxx>
Signed-off-by: Luis Henriques <luis.henriques@xxxxxxxxxxxxx>
---
drivers/cpuidle/driver.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

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;
--
1.9.1

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