| Message ID | 1453737174-1959778-1-git-send-email-arnd@arndb.de |
|---|---|
| State | New |
| Headers | show |
On 25/01/16 15:52, Arnd Bergmann wrote: > The ade7753_spi_read_reg_16() will either successfully read a value > from SPI, or return a failure code without delivering data. However, > the ade7753_stop_device() and ade7753_reset() functions use the returned > data without checking for an error condition first. Gcc detects this > as a possible bug and warns about it: > > drivers/staging/iio/meter/ade7753.c: In function 'ade7753_remove': > drivers/staging/iio/meter/ade7753.c:348:6: error: 'val' may be used uninitialized in this function [-Werror=maybe-uninitialized] > val |= BIT(4); /* AD converters can be turned off */ > ^ > drivers/staging/iio/meter/ade7753.c:345:6: note: 'val' was declared here > u16 val; > ^ > drivers/staging/iio/meter/ade7753.c: In function 'ade7753_probe': > drivers/staging/iio/meter/ade7753.c:222:6: error: 'val' may be used uninitialized in this function [-Werror=maybe-uninitialized] > > In both cases, we can avoids the warning by checking the return code > before using the data. > > Signed-off-by: Arnd Bergmann <arnd@arndb.de> Thanks. Applied to the togreg branch of iio.git - initially pushed out as testing for the autobuilders to play with it. Thanks, Jonathan > --- > drivers/staging/iio/meter/ade7753.c | 12 ++++++++++-- > 1 file changed, 10 insertions(+), 2 deletions(-) > > diff --git a/drivers/staging/iio/meter/ade7753.c b/drivers/staging/iio/meter/ade7753.c > index f129039bece3..69287108f793 100644 > --- a/drivers/staging/iio/meter/ade7753.c > +++ b/drivers/staging/iio/meter/ade7753.c > @@ -217,8 +217,12 @@ error_ret: > static int ade7753_reset(struct device *dev) > { > u16 val; > + int ret; > + > + ret = ade7753_spi_read_reg_16(dev, ADE7753_MODE, &val); > + if (ret) > + return ret; > > - ade7753_spi_read_reg_16(dev, ADE7753_MODE, &val); > val |= BIT(6); /* Software Chip Reset */ > > return ade7753_spi_write_reg_16(dev, ADE7753_MODE, val); > @@ -343,8 +347,12 @@ error_ret: > static int ade7753_stop_device(struct device *dev) > { > u16 val; > + int ret; > + > + ret = ade7753_spi_read_reg_16(dev, ADE7753_MODE, &val); > + if (ret) > + return ret; > > - ade7753_spi_read_reg_16(dev, ADE7753_MODE, &val); > val |= BIT(4); /* AD converters can be turned off */ > > return ade7753_spi_write_reg_16(dev, ADE7753_MODE, val); >
diff --git a/drivers/staging/iio/meter/ade7753.c b/drivers/staging/iio/meter/ade7753.c index f129039bece3..69287108f793 100644 --- a/drivers/staging/iio/meter/ade7753.c +++ b/drivers/staging/iio/meter/ade7753.c @@ -217,8 +217,12 @@ error_ret: static int ade7753_reset(struct device *dev) { u16 val; + int ret; + + ret = ade7753_spi_read_reg_16(dev, ADE7753_MODE, &val); + if (ret) + return ret; - ade7753_spi_read_reg_16(dev, ADE7753_MODE, &val); val |= BIT(6); /* Software Chip Reset */ return ade7753_spi_write_reg_16(dev, ADE7753_MODE, val); @@ -343,8 +347,12 @@ error_ret: static int ade7753_stop_device(struct device *dev) { u16 val; + int ret; + + ret = ade7753_spi_read_reg_16(dev, ADE7753_MODE, &val); + if (ret) + return ret; - ade7753_spi_read_reg_16(dev, ADE7753_MODE, &val); val |= BIT(4); /* AD converters can be turned off */ return ade7753_spi_write_reg_16(dev, ADE7753_MODE, val);
The ade7753_spi_read_reg_16() will either successfully read a value from SPI, or return a failure code without delivering data. However, the ade7753_stop_device() and ade7753_reset() functions use the returned data without checking for an error condition first. Gcc detects this as a possible bug and warns about it: drivers/staging/iio/meter/ade7753.c: In function 'ade7753_remove': drivers/staging/iio/meter/ade7753.c:348:6: error: 'val' may be used uninitialized in this function [-Werror=maybe-uninitialized] val |= BIT(4); /* AD converters can be turned off */ ^ drivers/staging/iio/meter/ade7753.c:345:6: note: 'val' was declared here u16 val; ^ drivers/staging/iio/meter/ade7753.c: In function 'ade7753_probe': drivers/staging/iio/meter/ade7753.c:222:6: error: 'val' may be used uninitialized in this function [-Werror=maybe-uninitialized] In both cases, we can avoids the warning by checking the return code before using the data. Signed-off-by: Arnd Bergmann <arnd@arndb.de> --- drivers/staging/iio/meter/ade7753.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) -- 2.7.0