Re: [PATCH v2] thermal: int340x: Protect trip temperature from dynamic update

On Mon, Jan 23, 2023 at 6:26 PM Srinivas Pandruvada srinivas.pandruvada@linux.intel.com wrote:

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().

Signed-off-by: Srinivas Pandruvada srinivas.pandruvada@linux.intel.com Cc: stable@vger.kernel.org # 5.0+

---

v2:

• rebased on linux-next

So I've rebased it back onto 6.2-rc5 and pushed the result into the thermal-intel-fixes branch. Please see if it looks good to you and let me know.

I'd prefer to push it for 6.2-rc.

• Add ret variable and remove return as suugested by Rafael

Thanks!

.../int340x_thermal/int340x_thermal_zone.c | 18 +++++++++++++++--- .../int340x_thermal/int340x_thermal_zone.h | 1 + 2 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/drivers/thermal/intel/int340x_thermal/int340x_thermal_zone.c b/drivers/thermal/intel/int340x_thermal/int340x_thermal_zone.c index 228f44260b27..5fda1e67b793 100644 --- a/drivers/thermal/intel/int340x_thermal/int340x_thermal_zone.c +++ b/drivers/thermal/intel/int340x_thermal/int340x_thermal_zone.c @@ -41,7 +41,9 @@ 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;
  

•   mutex_lock(&d->trip_mutex);
  
    if (trip < d->aux_trip_nr)
            *temp = d->aux_trips[trip];
  

@@ -60,10 +62,12 @@ 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, @@ -165,6 +169,8 @@ 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))
  

@@ -192,6 +198,8 @@ 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); @@ -215,6 +223,8 @@ 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->ops = kmemdup(&int340x_thermal_zone_ops,
  

@@ -277,6 +287,7 @@ struct int34x_thermal_zone *int340x_thermal_zone_add(struct acpi_device *adev, err_trip_alloc: kfree(int34x_thermal_zone->ops); err_ops_alloc:

•   mutex_destroy(&int34x_thermal_zone->trip_mutex);
    kfree(int34x_thermal_zone);
    return ERR_PTR(ret);
  

} @@ -289,6 +300,7 @@ void int340x_thermal_zone_remove(struct int34x_thermal_zone acpi_lpat_free_conversion_table(int34x_thermal_zone->lpat_table); kfree(int34x_thermal_zone->aux_trips); kfree(int34x_thermal_zone->ops);

•   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 e28ab1ba5e06..6610a9cc441b 100644 --- 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 *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 *,

2.31.1