| Message ID | 1542826891-28642-1-git-send-email-thara.gopinath@linaro.org (mailing list archive) |
|---|---|
| State | Changes Requested |
| Delegated to: | Zhang Rui |
| Headers | show |
| Series | thermal: Fix locking in cooling device sysfs update cur_state | expand |
On 21/11/2018 20:01, Thara Gopinath wrote: > Sysfs interface to update cooling device cur_state does not > currently hold cooling device lock, leading to stale values > in cur_state especially if getting updated simultanelously > from user space and thermal framework. Adding the proper locking > code fixes this issue. > > Signed-off-by: Thara Gopinath <thara.gopinath@linaro.org> > --- > drivers/thermal/thermal_sysfs.c | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) > > diff --git a/drivers/thermal/thermal_sysfs.c b/drivers/thermal/thermal_sysfs.c > index 2241cea..1f0c1e2 100644 > --- a/drivers/thermal/thermal_sysfs.c > +++ b/drivers/thermal/thermal_sysfs.c > @@ -712,10 +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) > + if (result) { > + mutex_unlock(&cdev->lock); > return result; > + } > thermal_cooling_device_stats_update(cdev, state); > + mutex_unlock(&cdev->lock); I suggest to invert the condition: mutex_lock(&cdev->lock); result = cdev->ops->set_cur_state(cdev, state); if (!result) thermal_cooling_device_stats_update(cdev, state); mutex_unlock(&cdev->lock); return result ? result : count; The same problem is there for the cur_state_show() callback.
diff --git a/drivers/thermal/thermal_sysfs.c b/drivers/thermal/thermal_sysfs.c index 2241cea..1f0c1e2 100644 --- a/drivers/thermal/thermal_sysfs.c +++ b/drivers/thermal/thermal_sysfs.c @@ -712,10 +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) + if (result) { + mutex_unlock(&cdev->lock); return result; + } thermal_cooling_device_stats_update(cdev, state); + mutex_unlock(&cdev->lock); return count; }
Sysfs interface to update cooling device cur_state does not currently hold cooling device lock, leading to stale values in cur_state especially if getting updated simultanelously from user space and thermal framework. Adding the proper locking code fixes this issue. Signed-off-by: Thara Gopinath <thara.gopinath@linaro.org> --- drivers/thermal/thermal_sysfs.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)