Commit 1b0a0e9a authored May 04, 2012 by Srivatsa S. Bhat Committed by Len Brown Jun 01, 2012

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>

parent 0aeb9cac

drivers/cpuidle/cpuidle.c

+6 −2

Original line number	Diff line number	Diff line
		@@ -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))) {