[PATCH] thermal: lock the thermal zone when switching governors

[PATCH] thermal: lock the thermal zone when switching governors

[Javi Merino]

Currently, userspace can request a governor change while the governor
itself is running.  Grab the thermal zone lock when changing the
governor to prevent this race.

Cc: Zhang Rui <rui.zhang@intel.com>
Cc: Eduardo Valentin <edubezval@gmail.com>
Signed-off-by: Javi Merino <javi.merino@arm.com>
---
 drivers/thermal/thermal_core.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
index 43b90709585f..c1901961f8c0 100644
--- a/drivers/thermal/thermal_core.c
+++ b/drivers/thermal/thermal_core.c
@@ -757,6 +757,7 @@ policy_store(struct device *dev, struct device_attribute *attr,
 	snprintf(name, sizeof(name), "%s", buf);
 
 	mutex_lock(&thermal_governor_lock);
+	mutex_lock(&tz->lock);
 
 	gov = __find_governor(strim(name));
 	if (!gov)
@@ -766,6 +767,7 @@ policy_store(struct device *dev, struct device_attribute *attr,
 	ret = count;
 
 exit:
+	mutex_unlock(&tz->lock);
 	mutex_unlock(&thermal_governor_lock);
 	return ret;
 }
-- 
1.9.1

Re: [PATCH] thermal: lock the thermal zone when switching governors

[Javi Merino]

Ping

On Tue, Nov 25, 2014 at 04:00:33PM +0000, Javi Merino wrote:
> Currently, userspace can request a governor change while the governor
> itself is running.  Grab the thermal zone lock when changing the
> governor to prevent this race.
> 
> Cc: Zhang Rui <rui.zhang@intel.com>
> Cc: Eduardo Valentin <edubezval@gmail.com>
> Signed-off-by: Javi Merino <javi.merino@arm.com>
> ---
>  drivers/thermal/thermal_core.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
> index 43b90709585f..c1901961f8c0 100644
> --- a/drivers/thermal/thermal_core.c
> +++ b/drivers/thermal/thermal_core.c
> @@ -757,6 +757,7 @@ policy_store(struct device *dev, struct device_attribute *attr,
>  	snprintf(name, sizeof(name), "%s", buf);
>  
>  	mutex_lock(&thermal_governor_lock);
> +	mutex_lock(&tz->lock);
>  
>  	gov = __find_governor(strim(name));
>  	if (!gov)
> @@ -766,6 +767,7 @@ policy_store(struct device *dev, struct device_attribute *attr,
>  	ret = count;
>  
>  exit:
> +	mutex_unlock(&tz->lock);
>  	mutex_unlock(&thermal_governor_lock);
>  	return ret;
>  }
> -- 
> 1.9.1
> 

Re: [PATCH] thermal: lock the thermal zone when switching governors

[Eduardo Valentin]

Hello,


On Wed, Dec 03, 2014 at 07:11:09PM +0000, Javi Merino wrote:
> Ping
> 
> On Tue, Nov 25, 2014 at 04:00:33PM +0000, Javi Merino wrote:
> > Currently, userspace can request a governor change while the governor
> > itself is running.  Grab the thermal zone lock when changing the
> > governor to prevent this race.
> > 
> > Cc: Zhang Rui <rui.zhang@intel.com>
> > Cc: Eduardo Valentin <edubezval@gmail.com>
> > Signed-off-by: Javi Merino <javi.merino@arm.com>

Acked-by: Eduardo Valentin <edubezval@gmail.com>

But I believe Rui has already merged this one. Just for the record
anyways.

> > ---
> >  drivers/thermal/thermal_core.c | 2 ++
> >  1 file changed, 2 insertions(+)
> > 
> > diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
> > index 43b90709585f..c1901961f8c0 100644
> > --- a/drivers/thermal/thermal_core.c
> > +++ b/drivers/thermal/thermal_core.c
> > @@ -757,6 +757,7 @@ policy_store(struct device *dev, struct device_attribute *attr,
> >  	snprintf(name, sizeof(name), "%s", buf);
> >  
> >  	mutex_lock(&thermal_governor_lock);
> > +	mutex_lock(&tz->lock);
> >  
> >  	gov = __find_governor(strim(name));
> >  	if (!gov)
> > @@ -766,6 +767,7 @@ policy_store(struct device *dev, struct device_attribute *attr,
> >  	ret = count;
> >  
> >  exit:
> > +	mutex_unlock(&tz->lock);
> >  	mutex_unlock(&thermal_governor_lock);
> >  	return ret;
> >  }
> > -- 
> > 1.9.1
> > 
>