ACPI/CPUIDLE: prevent setting pm_idle to NULL

[~andy/linux] / drivers / acpi / processor_idle.c

diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index b7f2963693a7b40fa2bc336dad5ae4cf0d9a8fbf..283c08f5f4d4390bfd12a7bfd820787a1344dbde 100644 (file)
--- 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