[FFmpeg-devel] [PATCH 2/5] avcodec/vp3: Call ff_progress_frame_unref() before ff_progress_frame_get_buffer()

[Andreas Rheinhardt]

Michael Niedermayer:
> Fixes: Assertion !f->f && !f->progress failed at libavcodec/decode.c:1688
> Fixes: 68190/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_THEORA_fuzzer-5942090287611904
> 
> Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
> Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
> ---
>  libavcodec/vp3.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/libavcodec/vp3.c b/libavcodec/vp3.c
> index 2a5f68dfa8e..09527607767 100644
> --- a/libavcodec/vp3.c
> +++ b/libavcodec/vp3.c
> @@ -2651,6 +2651,7 @@ static int vp3_decode_frame(AVCodecContext *avctx, AVFrame *frame,
>      if (avctx->skip_frame >= AVDISCARD_NONKEY && !s->keyframe)
>          return buf_size;
>  
> +    ff_progress_frame_unref(&s->current_frame);
>      ret = ff_progress_frame_get_buffer(avctx, &s->current_frame,
>                                         AV_GET_BUFFER_FLAG_REF);
>      if (ret < 0) {

LGTM.
(If I am not mistaken, this would have triggered the av_log(avctx,
AV_LOG_ERROR, "pic->data[*]!=NULL in get_buffer_internal\n") codepath
before switching to ProgressFrames, i.e. using an assert instead of
erroring out uncovered a bug. Maybe we should use an assert in
ff_get_buffer(), too?)

- Andreas