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@xxxxxxxxxxxxxxxxxx>
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@xxxxxxxxxxxxxxxxxx>
Acked-by: Daniel Lezcano <daniel.lezcano@xxxxxxxxxx>
Cc: Len Brown <lenb@xxxxxxxxxx>
Cc: "Brown, Len" <len.brown@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
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@xxxxxxxxxxxxxxxxxx are
cpuidle-add-checks-to-avoid-null-pointer-dereference.patch
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