thermal: hwmon: Make the check for critical temp valid consistent

On 05/21/2014 04:22 PM, Aaron Lu wrote:
> On 05/21/2014 01:57 PM, Kui Zhang wrote:
>> Hello,
>>
>> I get following error when rmmod thermal.
>>
>> rmmod  thermal
>> Killed

While dealing with this problem, I found another problem that also
results in a kernel crash on thermal module removal:

From: Aaron Lu <aaron.lu@intel.com>
Date: Wed, 21 May 2014 16:05:38 +0800
Subject: [PATCH] thermal: hwmon: Make the check for critical temp valid consistent

We used the tz->ops->get_crit_temp && !tz->ops->get_crit_temp(tz, temp)
to decide if we need to create the temp_crit attribute file but we just
check if tz->ops->get_crit_temp exists to decide if we need to remove
that attribute file. Some ACPI thermal zone doesn't have a valid critical
trip point and that would result in removing a non-existent device file
on thermal module unload.

Cc: All applicable <stable@vger.kernel.org>
Signed-off-by: Aaron Lu <aaron.lu@intel.com>
Signed-off-by: Zhang Rui <rui.zhang@intel.com>

diff --git a/drivers/thermal/thermal_hwmon.c b/drivers/thermal/thermal_hwmon.c
index fdb0719..1967bee 100644 (file)
--- a/drivers/thermal/thermal_hwmon.c
+++ b/drivers/thermal/thermal_hwmon.c
@@ -140,6 +140,12 @@ thermal_hwmon_lookup_temp(const struct thermal_hwmon_device *hwmon,
        return NULL;
 }
 
+static bool thermal_zone_crit_temp_valid(struct thermal_zone_device *tz)
+{
+       unsigned long temp;
+       return tz->ops->get_crit_temp && !tz->ops->get_crit_temp(tz, &temp);
+}
+
 int thermal_add_hwmon_sysfs(struct thermal_zone_device *tz)
 {
        struct thermal_hwmon_device *hwmon;
@@ -189,21 +195,18 @@ int thermal_add_hwmon_sysfs(struct thermal_zone_device *tz)
        if (result)
                goto free_temp_mem;
 
-       if (tz->ops->get_crit_temp) {
-               unsigned long temperature;
-               if (!tz->ops->get_crit_temp(tz, &temperature)) {
-                       snprintf(temp->temp_crit.name,
-                                sizeof(temp->temp_crit.name),
+       if (thermal_zone_crit_temp_valid(tz)) {
+               snprintf(temp->temp_crit.name,
+                               sizeof(temp->temp_crit.name),
                                "temp%d_crit", hwmon->count);
-                       temp->temp_crit.attr.attr.name = temp->temp_crit.name;
-                       temp->temp_crit.attr.attr.mode = 0444;
-                       temp->temp_crit.attr.show = temp_crit_show;
-                       sysfs_attr_init(&temp->temp_crit.attr.attr);
-                       result = device_create_file(hwmon->device,
-                                                   &temp->temp_crit.attr);
-                       if (result)
-                               goto unregister_input;
-               }
+               temp->temp_crit.attr.attr.name = temp->temp_crit.name;
+               temp->temp_crit.attr.attr.mode = 0444;
+               temp->temp_crit.attr.show = temp_crit_show;
+               sysfs_attr_init(&temp->temp_crit.attr.attr);
+               result = device_create_file(hwmon->device,
+                                           &temp->temp_crit.attr);
+               if (result)
+                       goto unregister_input;
        }
 
        mutex_lock(&thermal_hwmon_list_lock);
@@ -250,7 +253,7 @@ void thermal_remove_hwmon_sysfs(struct thermal_zone_device *tz)
        }
 
        device_remove_file(hwmon->device, &temp->temp_input.attr);
-       if (tz->ops->get_crit_temp)
+       if (thermal_zone_crit_temp_valid(tz))
                device_remove_file(hwmon->device, &temp->temp_crit.attr);
 
        mutex_lock(&thermal_hwmon_list_lock);