Messages in this thread | | | Subject | Re: [PATCH] thermal: Fix locking in cooling device sysfs update cur_state | From | Daniel Lezcano <> | Date | Wed, 21 Nov 2018 22:35:42 +0100 |
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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.
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