Messages in this thread Patch in this message | | | Subject | Re: [PATCH v4.4-rc8] iio: magnetometer: ak8975: Silence 'may be used uninitialized' warning | From | Srinivas Pandruvada <> | Date | Sat, 09 Jan 2016 08:17:09 -0800 |
| |
On Sat, 2016-01-09 at 16:00 +0000, Jonathan Cameron wrote: > On 09/01/16 00:17, tim.gardner@canonical.com wrote: > > From: Tim Gardner <tim.gardner@canonical.com> > > > > drivers/iio/magnetometer/ak8975.c: In function 'ak8975_probe': > > drivers/iio/magnetometer/ak8975.c:788:14: warning: 'chipset' may be > > used uninitialized in this function [-Wmaybe-uninitialized] > > data->def = &ak_def_array[chipset]; > > > > gcc version 5.3.1 20151219 (Ubuntu 5.3.1-4ubuntu1) > > > > Cc: Jonathan Cameron <jic23@kernel.org> > > Cc: Hartmut Knaack <knaack.h@gmx.de> > > Cc: Lars-Peter Clausen <lars@metafoo.de> > > Cc: Peter Meerwald <pmeerw@pmeerw.net> > > Cc: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> > > Signed-off-by: Tim Gardner <tim.gardner@canonical.com> > Doesn't look to be an actual bug as we either end up with chipset > being filled > based on the traditional match table in which case it'll be assigned > or based on the acpi match, which should succeed seeing as we've > already > had to have matched one or the other for the probe to match in the > first place. > > So probably worth the change to make it easier to tell that it should > be fine > and suppress the warning. However, whilst we are here, I note that > *match_acpi_table has a path which returns NULL as the name and > doesn't assign > the chipset. We should be therefore checking if (!name) return > -ENOSYS; > Though maybe another error code would be more appropriate. >
Since in this case we are enumerated by ACPI using our match table, so name can't be null. The "name" we provided in static const struct acpi_device_id ak_acpi_match[] = {..} Same with the *chipset. Other than suppress warnings, I don't think it will cause any real issue.
Thanks, Srinivas
> Not sure that error path can actually happen either, but if we are > going to > bother having the error path out of match_acpi_table then we ought to > actually > handle it! > > Don't suppose you'd mind fixing that one as well whilst here? > > Jonathan > > --- > > > > This seems like a legitimate warning, though gcc should have > > complained > > about an earlier use of chipset on line 782. > > > > drivers/iio/magnetometer/ak8975.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/drivers/iio/magnetometer/ak8975.c > > b/drivers/iio/magnetometer/ak8975.c > > index b13936d..80ec0ce 100644 > > --- a/drivers/iio/magnetometer/ak8975.c > > +++ b/drivers/iio/magnetometer/ak8975.c > > @@ -732,7 +732,7 @@ static int ak8975_probe(struct i2c_client > > *client, > > int eoc_gpio; > > int err; > > const char *name = NULL; > > - enum asahi_compass_chipset chipset; > > + enum asahi_compass_chipset chipset = AK_MAX_TYPE; > > > > /* Grab and set up the supplied GPIO. */ > > if (client->dev.platform_data) > > >
| |