[FFmpeg-devel] [PATCH] libavdevice/v4l2: fix of crash caused by assert

[Reimar Döffinger]

On Mon, Sep 01, 2014 at 10:33:15PM +0200, Giorgio Vazzana wrote:
> +static int enqueue_buffer(struct video_data *s, struct v4l2_buffer *buf)
> +{
> +    int res = 0;
> +
> +    if (v4l2_ioctl(s->fd, VIDIOC_QBUF, buf) < 0) {
> +        res = AVERROR(errno);
> +        av_log(NULL, AV_LOG_ERROR, "ioctl(VIDIOC_QBUF): %s\n", av_err2str(res));
> +    } else {
> +        avpriv_atomic_int_add_and_fetch(&s->buffers_queued, 1);
> +    }
> +
> +    return res;

Nit: I'd prefer something simpler that avoids cluttering the normal path
because of error handling like:

> +    if (v4l2_ioctl(s->fd, VIDIOC_QBUF, buf) < 0) {
> +        av_log(NULL, AV_LOG_ERROR, "ioctl(VIDIOC_QBUF): %s\n", av_err2str(res));
> +        return AVERROR(errno);
> +    }
> +    avpriv_atomic_int_add_and_fetch(&s->buffers_queued, 1);
> +    return 0;




>  static void mmap_release_buffer(void *opaque, uint8_t *data)

I haven't checked, but I suspect this function could be made simpler
and more likely to not re-introduce these bugs by using for the
error paths goto.
Admittedly that doesn't belong in this patch anyway though.