Patch[1/1]:ThermalFramework:Fix_crash_during_hwmon_unregister

Patch[1/1]:ThermalFramework:Fix_crash_during_hwmon_unregister

[R, Durgadoss]

Hi Len/Rui,

This patch fixes the following bug:
The thermal framework creates a temp*_crit interface, only when
the get_crit_temp pointer is defined. But during the _unregister_
path, without checking for the function definition, it is trying to
remove the temp*_crit interface.

There can be a situation, where a driver registers with the framework
and does not have a temp*_crit interface. When this driver attempts to
unregister, this will cause a kernel crash.

------------------------------------------------
From: Durgadoss R <durgadoss.r@intel.com>

Date: Thu, 20 Jan 2011 02:40:56 +0530
Subject: [PATCH] Thermal_Framework-Fix_crash_during_hwmon_unregister

This patch fixes the following bug:
The thermal framework creates a temp*_crit interface, only when
the get_crit_temp pointer is defined. But during the _unregister_
path, without checking for the function definition, it is trying to
remove the temp*_crit interface.

Signed-off-by: Durgadoss R <durgadoss.r@intel.com>

---
 drivers/thermal/thermal_sys.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/drivers/thermal/thermal_sys.c b/drivers/thermal/thermal_sys.c
index 13c72c6..eef2e14 100644
--- a/drivers/thermal/thermal_sys.c
+++ b/drivers/thermal/thermal_sys.c
@@ -556,7 +556,8 @@ thermal_remove_hwmon_sysfs(struct thermal_zone_device *tz)
 
 	tz->hwmon = NULL;
 	device_remove_file(hwmon->device, &tz->temp_input.attr);
-	device_remove_file(hwmon->device, &tz->temp_crit.attr);
+	if (tz->ops->get_crit_temp)
+		device_remove_file(hwmon->device, &tz->temp_crit.attr);
 
 	mutex_lock(&thermal_list_lock);
 	list_del(&tz->hwmon_node);
-- 
1.6.5.2

Patch[1/1]:ThermalFramework:Fix_crash_during_hwmon_unregister

[R, Durgadoss]

Hi Len/Rui,

Ping..Any comments/thoughts on this patch..?

> -----Original Message-----
> From: linux-acpi-owner@vger.kernel.org [mailto:linux-acpi-
> owner@vger.kernel.org] On Behalf Of R, Durgadoss
> Sent: Thursday, January 20, 2011 2:56 PM
> To: Len Brown; Zhang, Rui
> Cc: linux-acpi@vger.kernel.org
> Subject: Patch[1/1]:ThermalFramework:Fix_crash_during_hwmon_unregister
> 
> Hi Len/Rui,
> 
> This patch fixes the following bug:
> The thermal framework creates a temp*_crit interface, only when
> the get_crit_temp pointer is defined. But during the _unregister_
> path, without checking for the function definition, it is trying to
> remove the temp*_crit interface.
> 
> There can be a situation, where a driver registers with the framework
> and does not have a temp*_crit interface. When this driver attempts to
> unregister, this will cause a kernel crash.
> 
> ------------------------------------------------
> From: Durgadoss R <durgadoss.r@intel.com>
> 
> Date: Thu, 20 Jan 2011 02:40:56 +0530
> Subject: [PATCH] Thermal_Framework-Fix_crash_during_hwmon_unregister
> 
> This patch fixes the following bug:
> The thermal framework creates a temp*_crit interface, only when
> the get_crit_temp pointer is defined. But during the _unregister_
> path, without checking for the function definition, it is trying to
> remove the temp*_crit interface.
> 
> Signed-off-by: Durgadoss R <durgadoss.r@intel.com>
> 
> ---
>  drivers/thermal/thermal_sys.c |    3 ++-
>  1 files changed, 2 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/thermal/thermal_sys.c b/drivers/thermal/thermal_sys.c
> index 13c72c6..eef2e14 100644
> --- a/drivers/thermal/thermal_sys.c
> +++ b/drivers/thermal/thermal_sys.c
> @@ -556,7 +556,8 @@ thermal_remove_hwmon_sysfs(struct thermal_zone_device *tz)
> 
>  	tz->hwmon = NULL;
>  	device_remove_file(hwmon->device, &tz->temp_input.attr);
> -	device_remove_file(hwmon->device, &tz->temp_crit.attr);
> +	if (tz->ops->get_crit_temp)
> +		device_remove_file(hwmon->device, &tz->temp_crit.attr);
> 
>  	mutex_lock(&thermal_list_lock);
>  	list_del(&tz->hwmon_node);
> --
> 1.6.5.2
> 
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Re: Patch[1/1]:ThermalFramework:Fix_crash_during_hwmon_unregister

[Len Brown]

i think you may have some problems at
unregister_hwmon_device:

because we unconditionally device_remove_file() there,
even as the associated device_create_files failed.

please send just 1 copy of a patchin email,
and remember, as funky as it sounds, the comments
that are to be excluded from the check-in comment
go below the first '---'

thanks,
Len Brown, Intel Open Source Technology Center

RE: Patch[1/1]:ThermalFramework:Fix_crash_during_hwmon_unregister

[R, Durgadoss]

Hi Len,

> i think you may have some problems at
> unregister_hwmon_device:
> 
> because we unconditionally device_remove_file() there,
> even as the associated device_create_files failed.

Thanks for pointing it out. I missed it.
Shall send an appropriate patch.

> 
> please send just 1 copy of a patchin email,
> and remember, as funky as it sounds, the comments
> that are to be excluded from the check-in comment
> go below the first '---'

Shall take care of it from now on.

Thanks,
Durga