| Message ID | 20200321193107.21590-1-daniel.lezcano@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Delegated to: | Daniel Lezcano |
| Headers | show |
| Series | thermal/drivers/cpufreq_cooling: Remove abusing WARN_ON | expand |
On 21-03-20, 20:31, Daniel Lezcano wrote: > The WARN_ON macros are used at the entry functions state2power() and > set_cur_state(). > > state2power() is called with the max_state retrieved from > get_max_state which returns cpufreq_cdev->max_level, then it check if > max_state is > cpufreq_cdev->max_level. The test does not really makes > sense but let's assume we want to make sure to catch an error if the > code evolves. However the WARN_ON is overkill. > > set_cur_state() is also called from userspace if we write to the > sysfs. It is easy to see a stack dumped by just writing to sysfs > /sys/class/thermal/cooling_device0/cur_state a value greater than > "max_level". A bit scary. Returing -EINVAL is enough. > > Remove these WARN_ON. > > Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org> > --- > drivers/thermal/cpufreq_cooling.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/thermal/cpufreq_cooling.c b/drivers/thermal/cpufreq_cooling.c > index af55ac08e1bd..d66791a71320 100644 > --- a/drivers/thermal/cpufreq_cooling.c > +++ b/drivers/thermal/cpufreq_cooling.c > @@ -273,7 +273,7 @@ static int cpufreq_state2power(struct thermal_cooling_device *cdev, > struct cpufreq_cooling_device *cpufreq_cdev = cdev->devdata; > > /* Request state should be less than max_level */ > - if (WARN_ON(state > cpufreq_cdev->max_level)) > + if (state > cpufreq_cdev->max_level) > return -EINVAL; > > num_cpus = cpumask_weight(cpufreq_cdev->policy->cpus); > @@ -434,7 +434,7 @@ static int cpufreq_set_cur_state(struct thermal_cooling_device *cdev, > int ret; > > /* Request state should be less than max_level */ > - if (WARN_ON(state > cpufreq_cdev->max_level)) > + if (state > cpufreq_cdev->max_level) > return -EINVAL; > > /* Check if the old cooling action is same as new cooling action */ Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
On Sun, Mar 22, 2020 at 1:01 AM Daniel Lezcano <daniel.lezcano@linaro.org> wrote: > > The WARN_ON macros are used at the entry functions state2power() and > set_cur_state(). > > state2power() is called with the max_state retrieved from > get_max_state which returns cpufreq_cdev->max_level, then it check if > max_state is > cpufreq_cdev->max_level. The test does not really makes > sense but let's assume we want to make sure to catch an error if the > code evolves. However the WARN_ON is overkill. > > set_cur_state() is also called from userspace if we write to the > sysfs. It is easy to see a stack dumped by just writing to sysfs > /sys/class/thermal/cooling_device0/cur_state a value greater than > "max_level". A bit scary. Returing -EINVAL is enough. > > Remove these WARN_ON. > > Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org> Reviewed-by: Amit Kucheria <amit.kucheria@linaro.org> > --- > drivers/thermal/cpufreq_cooling.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/thermal/cpufreq_cooling.c b/drivers/thermal/cpufreq_cooling.c > index af55ac08e1bd..d66791a71320 100644 > --- a/drivers/thermal/cpufreq_cooling.c > +++ b/drivers/thermal/cpufreq_cooling.c > @@ -273,7 +273,7 @@ static int cpufreq_state2power(struct thermal_cooling_device *cdev, > struct cpufreq_cooling_device *cpufreq_cdev = cdev->devdata; > > /* Request state should be less than max_level */ > - if (WARN_ON(state > cpufreq_cdev->max_level)) > + if (state > cpufreq_cdev->max_level) > return -EINVAL; > > num_cpus = cpumask_weight(cpufreq_cdev->policy->cpus); > @@ -434,7 +434,7 @@ static int cpufreq_set_cur_state(struct thermal_cooling_device *cdev, > int ret; > > /* Request state should be less than max_level */ > - if (WARN_ON(state > cpufreq_cdev->max_level)) > + if (state > cpufreq_cdev->max_level) > return -EINVAL; > > /* Check if the old cooling action is same as new cooling action */ > -- > 2.17.1 >
diff --git a/drivers/thermal/cpufreq_cooling.c b/drivers/thermal/cpufreq_cooling.c index af55ac08e1bd..d66791a71320 100644 --- a/drivers/thermal/cpufreq_cooling.c +++ b/drivers/thermal/cpufreq_cooling.c @@ -273,7 +273,7 @@ static int cpufreq_state2power(struct thermal_cooling_device *cdev, struct cpufreq_cooling_device *cpufreq_cdev = cdev->devdata; /* Request state should be less than max_level */ - if (WARN_ON(state > cpufreq_cdev->max_level)) + if (state > cpufreq_cdev->max_level) return -EINVAL; num_cpus = cpumask_weight(cpufreq_cdev->policy->cpus); @@ -434,7 +434,7 @@ static int cpufreq_set_cur_state(struct thermal_cooling_device *cdev, int ret; /* Request state should be less than max_level */ - if (WARN_ON(state > cpufreq_cdev->max_level)) + if (state > cpufreq_cdev->max_level) return -EINVAL; /* Check if the old cooling action is same as new cooling action */
The WARN_ON macros are used at the entry functions state2power() and set_cur_state(). state2power() is called with the max_state retrieved from get_max_state which returns cpufreq_cdev->max_level, then it check if max_state is > cpufreq_cdev->max_level. The test does not really makes sense but let's assume we want to make sure to catch an error if the code evolves. However the WARN_ON is overkill. set_cur_state() is also called from userspace if we write to the sysfs. It is easy to see a stack dumped by just writing to sysfs /sys/class/thermal/cooling_device0/cur_state a value greater than "max_level". A bit scary. Returing -EINVAL is enough. Remove these WARN_ON. Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org> --- drivers/thermal/cpufreq_cooling.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)