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The FAN_RPM_TO_PERIOD() macro divides by "val" > > so a zero will crash the system. Check for that and return -EINVAL. > > > > Fixes: fc958a61ff6d ("hwmon: (adt7470) Convert to devm_hwmon_device_register_with_info API") > > Signed-off-by: Dan Carpenter > > --- > > drivers/hwmon/adt7470.c | 3 +++ > > 1 file changed, 3 insertions(+) > > > > diff --git a/drivers/hwmon/adt7470.c b/drivers/hwmon/adt7470.c > > index d519aca4a9d6..cd474584dc0b 100644 > > --- a/drivers/hwmon/adt7470.c > > +++ b/drivers/hwmon/adt7470.c > > @@ -662,6 +662,9 @@ static int adt7470_fan_write(struct device *dev, u32 attr, int channel, long val > > struct adt7470_data *data = dev_get_drvdata(dev); > > int err; > > + if (!val) > > + return -EINVAL; > > + > > Technically that restores old (pre-fc958a61ff6d) behavior, but it is still bad: > Userspace can provide a value of -1 (or any other negative number), and it will > translate to 5400000 RPM. So it should either be > > if (val <= 0) > return -EINVAL; > > or > if (val <= 0) > val = 1; There is a clamp() which does already turn invalid values into something valid. val = FAN_RPM_TO_PERIOD(val); val = clamp_val(val, 1, 65534); But I will make the <= 0 return -EINVAL change and resend. regards, dan carpenter