ACPI / PM: Fix possible NULL pointer deref in acpi_pm_device_sleep_state()
After commit fa1675b (ACPI / PM: Rework and clean up
acpi_dev_pm_get_state()) a NULL pointer dereference will take place
if NULL is passed to acpi_pm_device_sleep_state() as the second
argument.
Fix that by avoiding to use the pointer that may be NULL until
it's necessary to store a return value at the location pointed to
by it (if not NULL).
Reported-and-tested-by: Aaron Lu <aaron.lu@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
diff --git a/drivers/acpi/device_pm.c b/drivers/acpi/device_pm.c
index fd363b5..4c56dc8 100644
--- a/drivers/acpi/device_pm.c
+++ b/drivers/acpi/device_pm.c
@@ -521,7 +521,7 @@
{
acpi_handle handle = DEVICE_ACPI_HANDLE(dev);
struct acpi_device *adev;
- int ret, d_max;
+ int ret, d_min, d_max;
if (d_max_in < ACPI_STATE_D0 || d_max_in > ACPI_STATE_D3_COLD)
return -EINVAL;
@@ -540,19 +540,23 @@
}
ret = acpi_dev_pm_get_state(dev, adev, acpi_target_system_state(),
- d_min_p, &d_max);
+ &d_min, &d_max);
if (ret)
return ret;
- if (d_max_in < *d_min_p)
+ if (d_max_in < d_min)
return -EINVAL;
if (d_max > d_max_in) {
- for (d_max = d_max_in; d_max > *d_min_p; d_max--) {
+ for (d_max = d_max_in; d_max > d_min; d_max--) {
if (adev->power.states[d_max].flags.valid)
break;
}
}
+
+ if (d_min_p)
+ *d_min_p = d_min;
+
return d_max;
}
EXPORT_SYMBOL(acpi_pm_device_sleep_state);