1 files changed, 11 insertions, 4 deletions

diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index b7f2963693a7..283c08f5f4d4 100644
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -1332,9 +1332,15 @@ int acpi_processor_cst_has_changed(struct acpi_processor *pr)
         if (!pr->flags.power_setup_done)
                 return -ENODEV;
 
-        /* Fall back to the default idle loop */
-        pm_idle = pm_idle_save;
-        synchronize_sched();    /* Relies on interrupts forcing exit from idle. */
+        /*
+         * Fall back to the default idle loop, when pm_idle_save had
+         * been initialized.
+         */
+        if (pm_idle_save) {
+                pm_idle = pm_idle_save;
+                /* Relies on interrupts forcing exit from idle. */
+                synchronize_sched();
+        }
 
         pr->flags.power = 0;
         result = acpi_processor_get_power_info(pr);
@@ -1896,7 +1902,8 @@ int acpi_processor_power_exit(struct acpi_processor *pr,
 
         /* Unregister the idle handler when processor #0 is removed. */
         if (pr->id == 0) {
-                pm_idle = pm_idle_save;
+                if (pm_idle_save)
+                        pm_idle = pm_idle_save;
 
                 /*
                  * We are about to unload the current idle thread pm callback