thermal: intel: int340x: Protect trip temperature from concurrent updates

commit 6757a7abe47bcb12cb2d45661067e182424b0ee3 upstream.

Trip temperatures are read using ACPI methods and stored in the memory
during zone initializtion and when the firmware sends a notification for
change. This trip temperature is returned when the thermal core calls via
callback get_trip_temp().

But it is possible that while updating the memory copy of the trips when
the firmware sends a notification for change, thermal core is reading the
trip temperature via the callback get_trip_temp(). This may return invalid
trip temperature.

To address this add a mutex to protect the invalid temperature reads in
the callback get_trip_temp() and int340x_thermal_read_trips().

Fixes: 5fbf7f27fa3d ("Thermal/int340x: Add common thermal zone handler")
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Cc: 5.0+ <stable@vger.kernel.org> # 5.0+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/thermal/intel/int340x_thermal/int340x_thermal_zone.c b/drivers/thermal/intel/int340x_thermal/int340x_thermal_zone.c
index 62c0aa5..852f6c5 100644 (file)
--- a/drivers/thermal/intel/int340x_thermal/int340x_thermal_zone.c
+++ b/drivers/thermal/intel/int340x_thermal/int340x_thermal_zone.c
@@ -44,11 +44,13 @@ static int int340x_thermal_get_trip_temp(struct thermal_zone_device *zone,
                                         int trip, int *temp)
 {
        struct int34x_thermal_zone *d = zone->devdata;
-       int i;
+       int i, ret = 0;
 
        if (d->override_ops && d->override_ops->get_trip_temp)
                return d->override_ops->get_trip_temp(zone, trip, temp);
 
+       mutex_lock(&d->trip_mutex);
+
        if (trip < d->aux_trip_nr)
                *temp = d->aux_trips[trip];
        else if (trip == d->crt_trip_id)
@@ -66,10 +68,12 @@ static int int340x_thermal_get_trip_temp(struct thermal_zone_device *zone,
                        }
                }
                if (i == INT340X_THERMAL_MAX_ACT_TRIP_COUNT)
-                       return -EINVAL;
+                       ret = -EINVAL;
        }
 
-       return 0;
+       mutex_unlock(&d->trip_mutex);
+
+       return ret;
 }
 
 static int int340x_thermal_get_trip_type(struct thermal_zone_device *zone,
@@ -180,6 +184,8 @@ int int340x_thermal_read_trips(struct int34x_thermal_zone *int34x_zone)
        int trip_cnt = int34x_zone->aux_trip_nr;
        int i;
 
+       mutex_lock(&int34x_zone->trip_mutex);
+
        int34x_zone->crt_trip_id = -1;
        if (!int340x_thermal_get_trip_config(int34x_zone->adev->handle, "_CRT",
                                             &int34x_zone->crt_temp))
@@ -207,6 +213,8 @@ int int340x_thermal_read_trips(struct int34x_thermal_zone *int34x_zone)
                int34x_zone->act_trips[i].valid = true;
        }
 
+       mutex_unlock(&int34x_zone->trip_mutex);
+
        return trip_cnt;
 }
 EXPORT_SYMBOL_GPL(int340x_thermal_read_trips);
@@ -230,6 +238,8 @@ struct int34x_thermal_zone *int340x_thermal_zone_add(struct acpi_device *adev,
        if (!int34x_thermal_zone)
                return ERR_PTR(-ENOMEM);
 
+       mutex_init(&int34x_thermal_zone->trip_mutex);
+
        int34x_thermal_zone->adev = adev;
        int34x_thermal_zone->override_ops = override_ops;
 
@@ -281,6 +291,7 @@ err_thermal_zone:
        acpi_lpat_free_conversion_table(int34x_thermal_zone->lpat_table);
        kfree(int34x_thermal_zone->aux_trips);
 err_trip_alloc:
+       mutex_destroy(&int34x_thermal_zone->trip_mutex);
        kfree(int34x_thermal_zone);
        return ERR_PTR(ret);
 }
@@ -292,6 +303,7 @@ void int340x_thermal_zone_remove(struct int34x_thermal_zone
        thermal_zone_device_unregister(int34x_thermal_zone->zone);
        acpi_lpat_free_conversion_table(int34x_thermal_zone->lpat_table);
        kfree(int34x_thermal_zone->aux_trips);
+       mutex_destroy(&int34x_thermal_zone->trip_mutex);
        kfree(int34x_thermal_zone);
 }
 EXPORT_SYMBOL_GPL(int340x_thermal_zone_remove);

diff --git a/drivers/thermal/intel/int340x_thermal/int340x_thermal_zone.h b/drivers/thermal/intel/int340x_thermal/int340x_thermal_zone.h
index 3b4971d..8f9872a 100644 (file)
--- a/drivers/thermal/intel/int340x_thermal/int340x_thermal_zone.h
+++ b/drivers/thermal/intel/int340x_thermal/int340x_thermal_zone.h
@@ -32,6 +32,7 @@ struct int34x_thermal_zone {
        struct thermal_zone_device_ops *override_ops;
        void *priv_data;
        struct acpi_lpat_conversion_table *lpat_table;
+       struct mutex trip_mutex;
 };
 
 struct int34x_thermal_zone *int340x_thermal_zone_add(struct acpi_device *,