| Message ID | 1649985637-18854-1-git-send-email-baihaowen@meizu.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Headers | show |
| Series | [V2] iio: gp2ap020a00f: Fix signedness bug | expand |
On Fri, 15 Apr 2022 09:20:37 +0800 Haowen Bai <baihaowen@meizu.com> wrote: > function gp2ap020a00f_get_thresh_reg() is unsigned but returning -EINVAL > errcode, and thresh_reg_l is unsigned but receiving -EINVAL errcode. so > we have to change u8 -> int. > > Signed-off-by: Haowen Bai <baihaowen@meizu.com> Hi, The return value is not checked in *read_event_val(), so if we actually got -EINVAL (in reality we can't because the switch in *_get_thresh_reg*) always matches) then we'd use it to index an array (after performing some maths on the value). So please also add a check that the return value is not negative in read_event_val() Same is true or write_event_val. Note that the bug here is probably the fact we return -EINVAL in the first place. We could just stop doing that but it would be non obvious when looking at the code that we couldn't get a failure to match in the switch statement - so fixing as you have done (plus the extra check I'm requesting) is probably the neatest solution. Thanks, Jonathan > --- > V1->V2: s8 is not enough to hold an (arbitrary) error code. To be on the safe > side we need to use int > > drivers/iio/light/gp2ap020a00f.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/drivers/iio/light/gp2ap020a00f.c b/drivers/iio/light/gp2ap020a00f.c > index b820041159f7..b0e62d3c6fa0 100644 > --- a/drivers/iio/light/gp2ap020a00f.c > +++ b/drivers/iio/light/gp2ap020a00f.c > @@ -994,7 +994,7 @@ static irqreturn_t gp2ap020a00f_trigger_handler(int irq, void *data) > return IRQ_HANDLED; > } > > -static u8 gp2ap020a00f_get_thresh_reg(const struct iio_chan_spec *chan, > +static int gp2ap020a00f_get_thresh_reg(const struct iio_chan_spec *chan, > enum iio_event_direction event_dir) > { > switch (chan->type) { > @@ -1025,7 +1025,7 @@ static int gp2ap020a00f_write_event_val(struct iio_dev *indio_dev, > struct gp2ap020a00f_data *data = iio_priv(indio_dev); > bool event_en = false; > u8 thresh_val_id; > - u8 thresh_reg_l; > + int thresh_reg_l; > int err = 0; > > mutex_lock(&data->lock); > @@ -1082,7 +1082,7 @@ static int gp2ap020a00f_read_event_val(struct iio_dev *indio_dev, > int *val, int *val2) > { > struct gp2ap020a00f_data *data = iio_priv(indio_dev); > - u8 thresh_reg_l; > + int thresh_reg_l; > int err = IIO_VAL_INT; > > mutex_lock(&data->lock);
在 4/16/22 1:52 AM, Jonathan Cameron 写道: > On Fri, 15 Apr 2022 09:20:37 +0800 > Haowen Bai <baihaowen@meizu.com> wrote: > >> function gp2ap020a00f_get_thresh_reg() is unsigned but returning -EINVAL >> errcode, and thresh_reg_l is unsigned but receiving -EINVAL errcode. so >> we have to change u8 -> int. >> >> Signed-off-by: Haowen Bai <baihaowen@meizu.com> > Hi, > > The return value is not checked in *read_event_val(), so if we actually got > -EINVAL (in reality we can't because the switch in *_get_thresh_reg*) always > matches) then we'd use it to index an array (after performing some maths on > the value). So please also add a check that the return value is not > negative in read_event_val() > > Same is true or write_event_val. > > > Note that the bug here is probably the fact we return -EINVAL in the > first place. We could just stop doing that but it would be non obvious > when looking at the code that we couldn't get a failure to match in > the switch statement - so fixing as you have done (plus the extra > check I'm requesting) is probably the neatest solution. > > Thanks, > > Jonathan > > >> --- >> V1->V2: s8 is not enough to hold an (arbitrary) error code. To be on the safe >> side we need to use int >> >> drivers/iio/light/gp2ap020a00f.c | 6 +++--- >> 1 file changed, 3 insertions(+), 3 deletions(-) >> >> diff --git a/drivers/iio/light/gp2ap020a00f.c b/drivers/iio/light/gp2ap020a00f.c >> index b820041159f7..b0e62d3c6fa0 100644 >> --- a/drivers/iio/light/gp2ap020a00f.c >> +++ b/drivers/iio/light/gp2ap020a00f.c >> @@ -994,7 +994,7 @@ static irqreturn_t gp2ap020a00f_trigger_handler(int irq, void *data) >> return IRQ_HANDLED; >> } >> >> -static u8 gp2ap020a00f_get_thresh_reg(const struct iio_chan_spec *chan, >> +static int gp2ap020a00f_get_thresh_reg(const struct iio_chan_spec *chan, >> enum iio_event_direction event_dir) >> { >> switch (chan->type) { >> @@ -1025,7 +1025,7 @@ static int gp2ap020a00f_write_event_val(struct iio_dev *indio_dev, >> struct gp2ap020a00f_data *data = iio_priv(indio_dev); >> bool event_en = false; >> u8 thresh_val_id; >> - u8 thresh_reg_l; >> + int thresh_reg_l; >> int err = 0; >> >> mutex_lock(&data->lock); >> @@ -1082,7 +1082,7 @@ static int gp2ap020a00f_read_event_val(struct iio_dev *indio_dev, >> int *val, int *val2) >> { >> struct gp2ap020a00f_data *data = iio_priv(indio_dev); >> - u8 thresh_reg_l; >> + int thresh_reg_l; >> int err = IIO_VAL_INT; >> >> mutex_lock(&data->lock); hi Jonathan Cameron Thank you for your suggestion. resended :).
diff --git a/drivers/iio/light/gp2ap020a00f.c b/drivers/iio/light/gp2ap020a00f.c index b820041159f7..b0e62d3c6fa0 100644 --- a/drivers/iio/light/gp2ap020a00f.c +++ b/drivers/iio/light/gp2ap020a00f.c @@ -994,7 +994,7 @@ static irqreturn_t gp2ap020a00f_trigger_handler(int irq, void *data) return IRQ_HANDLED; } -static u8 gp2ap020a00f_get_thresh_reg(const struct iio_chan_spec *chan, +static int gp2ap020a00f_get_thresh_reg(const struct iio_chan_spec *chan, enum iio_event_direction event_dir) { switch (chan->type) { @@ -1025,7 +1025,7 @@ static int gp2ap020a00f_write_event_val(struct iio_dev *indio_dev, struct gp2ap020a00f_data *data = iio_priv(indio_dev); bool event_en = false; u8 thresh_val_id; - u8 thresh_reg_l; + int thresh_reg_l; int err = 0; mutex_lock(&data->lock); @@ -1082,7 +1082,7 @@ static int gp2ap020a00f_read_event_val(struct iio_dev *indio_dev, int *val, int *val2) { struct gp2ap020a00f_data *data = iio_priv(indio_dev); - u8 thresh_reg_l; + int thresh_reg_l; int err = IIO_VAL_INT; mutex_lock(&data->lock);
function gp2ap020a00f_get_thresh_reg() is unsigned but returning -EINVAL errcode, and thresh_reg_l is unsigned but receiving -EINVAL errcode. so we have to change u8 -> int. Signed-off-by: Haowen Bai <baihaowen@meizu.com> --- V1->V2: s8 is not enough to hold an (arbitrary) error code. To be on the safe side we need to use int drivers/iio/light/gp2ap020a00f.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)