2018-11-27 22:46:10

by Thara Gopinath

Subject: [PATCH V2] thermal: Fix locking in cooling device sysfs update cur_state

Sysfs interface to update cooling device cur_state does not
currently holding cooling device lock sometimes leading to
stale values in cur_state if getting updated simultanelously
from user space and thermal framework. Adding the proper locking
code fixes this issue.

Signed-off-by: Thara Gopinath <[email protected]>
---

V1->V2: Rearranged the code as per Daniel's review comment

drivers/thermal/thermal_sysfs.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/drivers/thermal/thermal_sysfs.c b/drivers/thermal/thermal_sysfs.c
index 2241cea..aa99edb 100644
--- a/drivers/thermal/thermal_sysfs.c
+++ b/drivers/thermal/thermal_sysfs.c
@@ -712,11 +712,14 @@ cur_state_store(struct device *dev, struct device_attribute *attr,
if ((long)state < 0)
return -EINVAL;

+ mutex_lock(&cdev->lock);
+
result = cdev->ops->set_cur_state(cdev, state);
- if (result)
- return result;
- thermal_cooling_device_stats_update(cdev, state);
- return count;
+ if (!result)
+ thermal_cooling_device_stats_update(cdev, state);
+
+ mutex_unlock(&cdev->lock);
+ return result ? result : count;
}

static struct device_attribute
--
2.1.4

2019-01-03 06:06:43

by Thara Gopinath

Subject: Re: [PATCH V2] thermal: Fix locking in cooling device sysfs update cur_state

On 11/27/2018 05:43 PM, Thara Gopinath wrote:
> Sysfs interface to update cooling device cur_state does not
> currently holding cooling device lock sometimes leading to
> stale values in cur_state if getting updated simultanelously
> from user space and thermal framework. Adding the proper locking
> code fixes this issue.
>
> Signed-off-by: Thara Gopinath <[email protected]>
> ---
>
> V1->V2: Rearranged the code as per Daniel's review comment

Hi Eduardo, Daniel

Any comments on this ?

Regards
Thara

>
> drivers/thermal/thermal_sysfs.c | 11 +++++++----
> 1 file changed, 7 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/thermal/thermal_sysfs.c b/drivers/thermal/thermal_sysfs.c
> index 2241cea..aa99edb 100644
> --- a/drivers/thermal/thermal_sysfs.c
> +++ b/drivers/thermal/thermal_sysfs.c
> @@ -712,11 +712,14 @@ cur_state_store(struct device *dev, struct device_attribute *attr,
> if ((long)state < 0)
> return -EINVAL;
>
> + mutex_lock(&cdev->lock);
> +
> result = cdev->ops->set_cur_state(cdev, state);
> - if (result)
> - return result;
> - thermal_cooling_device_stats_update(cdev, state);
> - return count;
> + if (!result)
> + thermal_cooling_device_stats_update(cdev, state);
> +
> + mutex_unlock(&cdev->lock);
> + return result ? result : count;
> }
>
> static struct device_attribute
>

2019-01-03 06:31:08

by Zhang, Rui

Subject: Re: [PATCH V2] thermal: Fix locking in cooling device sysfs update cur_state

On 三, 2019-01-02 at 21:29 -0500, Thara Gopinath wrote:
> On 11/27/2018 05:43 PM, Thara Gopinath wrote:
> >
> > Sysfs interface to update cooling device cur_state does not
> > currently holding cooling device lock sometimes leading to
> > stale values in cur_state if getting updated simultanelously
> > from user space and thermal framework. Adding the proper locking
> > code fixes this issue.
> >
> > Signed-off-by: Thara Gopinath <[email protected]>
> > ---
> >
> > V1->V2: Rearranged the code as per Daniel's  review comment 
> Hi Eduardo, Daniel
>
> Any comments on this ?
>
it's already in my tree, and will be included in my pull request which
will be sent out soon.

thanks,
rui

> Regards
> Thara
>
> >
> >
> >  drivers/thermal/thermal_sysfs.c | 11 +++++++----
> >  1 file changed, 7 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/thermal/thermal_sysfs.c
> > b/drivers/thermal/thermal_sysfs.c
> > index 2241cea..aa99edb 100644
> > --- a/drivers/thermal/thermal_sysfs.c
> > +++ b/drivers/thermal/thermal_sysfs.c
> > @@ -712,11 +712,14 @@ cur_state_store(struct device *dev, struct
> > device_attribute *attr,
> >   if ((long)state < 0)
> >   return -EINVAL;
> >  
> > + mutex_lock(&cdev->lock);
> > +
> >   result = cdev->ops->set_cur_state(cdev, state);
> > - if (result)
> > - return result;
> > - thermal_cooling_device_stats_update(cdev, state);
> > - return count;
> > + if (!result)
> > + thermal_cooling_device_stats_update(cdev, state);
> > +
> > + mutex_unlock(&cdev->lock);
> > + return result ? result : count;
> >  }
> >  
> >  static struct device_attribute
> >
>
>