help with memory leak

Hi, this C function is leaking memory:

AV* __next_subset(SV* data_avptr, SV* odometer_avptr)
{
    AV* data     = GETAV(data_avptr);
    AV* odometer = GETAV(odometer_avptr);
    I32 len_data = av_len(data);
    AV* subset   = newAV();
    IV adjust    = 1;
    int i;
    IV n;

    for (i = 0; i <= len_data; ++i) {
        n = GETIV(odometer, i);
        if (n) {
            av_push(subset, newSVsv(*av_fetch(data, i, 0)));
        }
        if (adjust) {
            adjust = 1 - n;
            SETIV(odometer, i, adjust);
        }
    }

    return subset;
}

I think the problem is the reference count of the AV*. Is that
correct? How should I build/return it to prevent that?