piolib: Posible dereference of a null pointer: piolib.c line 118

[Gebhartj]

Automated analysis found:

Warning: line 119, column 11 in file piolib.c
Access to field 'chip' results in a dereference of a null pointer (loaded from variable 'pio')

Unsure if this is a real issue.

@pelwell thanks for recent fixes.

If you'd like to see the generated interactive HTML report, mention me and I will publish it.

[pelwell]

Thanks, for the report. I'm certain it's not a real issue, because of the following lines (https://github.com/raspberrypi/utils/blob/master/piolib/piolib.c#L74-L75):

        if (pio && !PIO_IS_ERR(pio)) {
            pio_instances[num_instances++] = pio;

Prior to this, num_instances is initialised to 0, and that will be the default value because it is a static variable.

The second line is the only other place where num_instances is assigned to, and this happens only if pio is non-NULL, so I claim that the values in the pio_instances array up to but not including pio_instances[num_instances] must always be non-NULL.