ACPI : Check parameter when calling acpi_processor_get/set_throttling

It is necessary to check the parameter when calling the function of
acpi_processor_get/set_throttling function so as to avoid the NULL
pointer reference in pr or throttling.

http://bugzilla.kernel.org/show_bug.cgi?id=9747

Signed-off-by: Zhao Yakui <yakui.zhao@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

drivers/acpi/processor_throttling.c

diff --git a/drivers/acpi/processor_throttling.c b/drivers/acpi/processor_throttling.c
index 1685b40a..5d2eae2 100644
--- a/drivers/acpi/processor_throttling.c
+++ b/drivers/acpi/processor_throttling.c
@@ -589,6 +589,11 @@
 	cpumask_t saved_mask;
 	int ret;
 
+	if (!pr)
+		return -EINVAL;
+
+	if (!pr->flags.throttling)
+		return -ENODEV;
 	/*
 	 * Migrate task to the cpu pointed by pr.
 	 */
@@ -743,6 +748,16 @@
 {
 	cpumask_t saved_mask;
 	int ret;
+
+	if (!pr)
+		return -EINVAL;
+
+	if (!pr->flags.throttling)
+		return -ENODEV;
+
+	if ((state < 0) || (state > (pr->throttling.state_count - 1)))
+		return -EINVAL;
+
 	/*
 	 * Migrate task to the cpu pointed by pr.
 	 */