On Tue, Jan 24, 2012 at 03:50:12AM -0500, Jean Delvare wrote: > Hi Guenter, > > On Mon, 23 Jan 2012 18:49:58 -0800, Guenter Roeck wrote: > > When updating vrm, the value range was not limited. This could result in more or > > less random vrm values if the value provided by the user was larger than 255. > > Fix by limiting the range to 0..255 using the SENSORS_LIMIT macro. > > > > Cc: Jean Delvare <khali@xxxxxxxxxxxx> > > Signed-off-by: Guenter Roeck <guenter.roeck@xxxxxxxxxxxx> > > --- > > drivers/hwmon/it87.c | 2 +- > > 1 files changed, 1 insertions(+), 1 deletions(-) > > > > diff --git a/drivers/hwmon/it87.c b/drivers/hwmon/it87.c > > index 0b204e4..bd8775c 100644 > > --- a/drivers/hwmon/it87.c > > +++ b/drivers/hwmon/it87.c > > @@ -1324,7 +1324,7 @@ static ssize_t store_vrm_reg(struct device *dev, struct device_attribute *attr, > > if (kstrtoul(buf, 10, &val) < 0) > > return -EINVAL; > > > > - data->vrm = val; > > + data->vrm = SENSORS_LIMIT(val, 0, 255); > > > > return count; > > } > > To be honest, I don't know what to do with this. > > You're replacing a silent failure with another. I'd rather return an > error if the value doesn't fit. as clamping to 255 will lead to a > failure in vid_from_reg() later anyway. > > On the other hand, we don't validate the VRM value here anyway, it > could be in the 0-255 range and still lead to a failure in > vid_from_reg(). > > We could improve this of course, but is it worth it? As documented in > Documentation/hwmon/sysfs-interface, changing the vrm value manually > should no longer be needed. libsensors does even ignore this attribute > completely. And newer hardware tends to no longer use the VID pins at > all. Actually hwmon-vid is in a pretty bad shape at the moment at least > for all Intel CPUs after Conroe (2007, yeah!) for which we set the VRM > to 82 i.e. Pentium II/III. And nobody complained yet as far as I know! > If it is like me, I always thought it was a chip problem that it displays a voltage of 0. There is no warning, so my take is that people simply don't realize that the CPU model is not recognized. > So I'm really not sure if it is worth spending time on. It might make > more sense to turn all these vrm attributes read-only (and ultimately > kill them altogether.) If we really want to let the user force the vrm > value if automatic detection failed, it would probably be better done > as a module parameter to hwmon-vid. It is certainly less flexible, but > at least we don't have to repeat it in every hwmon driver. > After looking into it a bit more, I think we should move the vrm attributes to hwmon-vid (and fix hwmon-vid). Guenter _______________________________________________ lm-sensors mailing list lm-sensors@xxxxxxxxxxxxxx http://lists.lm-sensors.org/mailman/listinfo/lm-sensors
