Messages in this thread Patch in this message | | | Date | Mon, 30 Apr 2012 12:30:55 +0530 | From | "Srivatsa S. Bhat" <> | Subject | [PATCH v2][RESEND] cpuidle: Add checks to avoid NULL pointer dereference |
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From: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
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> ---
drivers/cpuidle/cpuidle.c | 8 ++++++-- 1 files changed, 6 insertions(+), 2 deletions(-)
diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c index 87411ce..eae2f11 100644 --- a/drivers/cpuidle/cpuidle.c +++ b/drivers/cpuidle/cpuidle.c @@ -291,6 +291,9 @@ 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) @@ -375,8 +378,6 @@ 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;
@@ -401,6 +402,9 @@ int cpuidle_register_device(struct cpuidle_device *dev) { int ret;
+ if (!dev) + return -EINVAL; + mutex_lock(&cpuidle_lock);
if ((ret = __cpuidle_register_device(dev))) {
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