Re: [PATCH v5 05/10] iio: light: gp2ap020a00f: Fix possible error swallow

[Jonathan Cameron]

On Mon, 23 Feb 2026 14:05:19 +0200
Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> wrote:

> On Sun, Feb 22, 2026 at 09:40:15PM -0600, Ethan Tidmore wrote:
> > Move error check into for loop in gp2ap020a00f_buffer_postenable() and
> > gp2ap020a00f_buffer_predisable(), this fixes a possible error swallow.  
> 
> ...
> 
> > -	int i, err = 0;
> > +	int i, err;  
> 
> I believe we can't do that without introducing a 'default' case.

I agree. I'm a bit confused why LLVM at least isn't moaning about this.

Anyhow, I'm not sure why it defaulted to 0 previously...

diff --git a/drivers/iio/light/gp2ap020a00f.c b/drivers/iio/light/gp2ap020a00f.c
index d2156e133b75..64be9b8ca5e3 100644
--- a/drivers/iio/light/gp2ap020a00f.c
+++ b/drivers/iio/light/gp2ap020a00f.c
@@ -1365,6 +1365,9 @@ static int gp2ap020a00f_buffer_postenable(struct iio_dev *indio_dev)
                        err = gp2ap020a00f_exec_cmd(data,
                                        GP2AP020A00F_CMD_TRIGGER_PROX_EN);
                        break;
+               default:
+                       err = -EINVAL;
+                       break;
                }
                if (err)
                        return err;
@@ -1398,6 +1401,9 @@ static int gp2ap020a00f_buffer_predisable(struct iio_dev *indio_dev)
                        err = gp2ap020a00f_exec_cmd(data,
                                        GP2AP020A00F_CMD_TRIGGER_PROX_DIS);
                        break;
+               default:
+                       err = -EINVAL;
+                       break;
                }
                if (err)
                        return err;

Is the tweak I applied to resolve this.

Thanks,

Jonathan

> 
> >  	guard(mutex)(&data->lock);
> >  
> > @@ -1366,11 +1366,10 @@ static int gp2ap020a00f_buffer_postenable(struct iio_dev *indio_dev)
> >  					GP2AP020A00F_CMD_TRIGGER_PROX_EN);
> >  			break;
> >  		}
> > +		if (err)
> > +			return err;
> >  	}
> >  
> > -	if (err < 0)
> > -		return err;  
> 
> (Also you might want to mention dropping '< 0' for making the style consistent
>  taking into account that those functions won't return any positive values.)
> 
> >  	data->buffer = kmalloc(indio_dev->scan_bytes, GFP_KERNEL);
> >  	if (!data->buffer)
> >  		return -ENOMEM;
> > @@ -1381,7 +1380,7 @@ static int gp2ap020a00f_buffer_postenable(struct iio_dev *indio_dev)
> >  static int gp2ap020a00f_buffer_predisable(struct iio_dev *indio_dev)
> >  {
> >  	struct gp2ap020a00f_data *data = iio_priv(indio_dev);
> > -	int i, err = 0;
> > +	int i, err;  
> 
> Ditto.
> 
> >  	guard(mutex)(&data->lock);
> >  
> > @@ -1400,11 +1399,10 @@ static int gp2ap020a00f_buffer_predisable(struct iio_dev *indio_dev)
> >  					GP2AP020A00F_CMD_TRIGGER_PROX_DIS);
> >  			break;
> >  		}
> > +		if (err)
> > +			return err;
> >  	}
> >  
> > -	if (err)
> > -		return err;
> > -
> >  	kfree(data->buffer);
> >  	return 0;
> >  }  
>