+ cpuidle-add-checks-to-avoid-null-pointer-dereference.patch added to -mm tree

+ cpuidle-add-checks-to-avoid-null-pointer-dereference.patch added to -mm tree

[akpm]

The patch titled
     Subject: cpuidle: add checks to avoid NULL pointer dereference
has been added to the -mm tree.  Its filename is
     cpuidle-add-checks-to-avoid-null-pointer-dereference.patch

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------------------------------------------------------
From: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Subject: 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>
Cc: Len Brown <lenb@kernel.org>
Cc: "Brown, Len" <len.brown@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 drivers/cpuidle/cpuidle.c |    8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff -puN drivers/cpuidle/cpuidle.c~cpuidle-add-checks-to-avoid-null-pointer-dereference drivers/cpuidle/cpuidle.c
--- a/drivers/cpuidle/cpuidle.c~cpuidle-add-checks-to-avoid-null-pointer-dereference
+++ a/drivers/cpuidle/cpuidle.c
@@ -285,6 +285,9 @@ int cpuidle_enable_device(struct cpuidle
 	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(str
 	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 cpuid
 {
 	int ret;
 
+	if (!dev)
+		return -EINVAL;
+
 	mutex_lock(&cpuidle_lock);
 
 	if ((ret = __cpuidle_register_device(dev))) {
_
Subject: Subject: cpuidle: add checks to avoid NULL pointer dereference

Patches currently in -mm which might be from srivatsa.bhat@linux.vnet.ibm.com are

cpuidle-add-checks-to-avoid-null-pointer-dereference.patch