ACPI: prevent processor.max_cstate=0 boot crash

As processor.max_cstate is an init-time-only modparam,
sanity checking it at init-time is sufficient.

http://bugzilla.kernel.org/show_bug.cgi?id=13142

Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index 6fe121434ffb..436127e0eec3 100644
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -1037,6 +1037,9 @@ static int acpi_processor_setup_cpuidle(struct acpi_processor *pr)
                 dev->states[i].desc[0] = '\0';
         }
 
+        if (max_cstate == 0)
+                max_cstate = 1;
+
         for (i = 1; i < ACPI_PROCESSOR_MAX_POWER && i <= max_cstate; i++) {
                 cx = &pr->power.states[i];
                 state = &dev->states[count];