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>

1 files changed, 18 insertions, 15 deletions

diff --git a/drivers/thermal/thermal_hwmon.c b/drivers/thermal/thermal_hwmon.c
index fdb07199d9c2..1967bee4f076 100644
--- 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);