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cpuidle: add checks to avoid NULL pointer dereference 

The existing check for dev == NULL in __cpuidle_register_device() is
rendered useless because dev is dereferenced before the check itself.
Moreover, correctly speaking, it is the job of the callers of this
function, i.e., cpuidle_register_device() & cpuidle_enable_device() (which
also happen to be exported functions) to ensure that
__cpuidle_register_device() is called with a non-NULL dev.

So add the necessary dev == NULL checks in the two callers and remove the
(useless) check from __cpuidle_register_device().

Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Len Brown <len.brown@intel.com>
This commit is contained in:
Srivatsa S. Bhat 2012-05-04 14:06:02 -07:00 committed by Len Brown
parent 0aeb9cac6f
commit 1b0a0e9a15
1 changed files with 6 additions and 2 deletions
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8
drivers/cpuidle/cpuidle.c
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@ -285,6 +285,9 @@ int cpuidle_enable_device(struct cpuidle_device *dev)
int ret, i;
struct cpuidle_driver *drv = cpuidle_get_driver();
if (!dev)
return -EINVAL;
if (dev->enabled)
return 0;
if (!drv || !cpuidle_curr_governor)
@ -369,8 +372,6 @@ static int __cpuidle_register_device(struct cpuidle_device *dev)
struct device *cpu_dev = get_cpu_device((unsigned long)dev->cpu);
struct cpuidle_driver *cpuidle_driver = cpuidle_get_driver();
if (!dev)
return -EINVAL;
if (!try_module_get(cpuidle_driver->owner))
return -EINVAL;
@ -395,6 +396,9 @@ int cpuidle_register_device(struct cpuidle_device *dev)
{
int ret;
if (!dev)
return -EINVAL;
mutex_lock(&cpuidle_lock);
if ((ret = __cpuidle_register_device(dev))) {