[FFmpeg-devel] [PATCH] avcodec/cuviddec: fix CUDA_ERROR_INVALID_CONTEXT error found by cuda-memcheck tool

[Timo Rothenpieler]

On 18.11.2020 09:24, leozhang wrote:
> Test command like below:
> cuda-memcheck ./ffmpeg -hwaccel cuvid -c:v h264_cuvid -i input_file -c:v h264_nvenc -f null -
> 
> Signed-off-by: leozhang <nowerzt at gmail.com>
> ---
>   libavcodec/cuviddec.c | 15 +++++++++++++++
>   1 file changed, 15 insertions(+)
> 
> diff --git a/libavcodec/cuviddec.c b/libavcodec/cuviddec.c
> index 5e698d4cd0..816a9c1b3c 100644
> --- a/libavcodec/cuviddec.c
> +++ b/libavcodec/cuviddec.c
> @@ -673,15 +673,27 @@ static int cuvid_decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
>   static av_cold int cuvid_decode_end(AVCodecContext *avctx)
>   {
>       CuvidContext *ctx = avctx->priv_data;
> +    AVHWDeviceContext *device_ctx = (AVHWDeviceContext *)ctx->hwdevice->data;
> +    AVCUDADeviceContext *device_hwctx = device_ctx->hwctx;
> +    CUcontext dummy, cuda_ctx = device_hwctx->cuda_ctx;
> +    int ret;
>   
>       av_fifo_freep(&ctx->frame_queue);
>   
> +    ret = CHECK_CU(ctx->cudl->cuCtxPushCurrent(cuda_ctx));
> +    if (ret < 0)
> +        goto error;
> +
>       if (ctx->cuparser)
>           ctx->cvdl->cuvidDestroyVideoParser(ctx->cuparser);
>   
>       if (ctx->cudecoder)
>           ctx->cvdl->cuvidDestroyDecoder(ctx->cudecoder);
>   
> +    ret = CHECK_CU(ctx->cudl->cuCtxPopCurrent(&dummy));
> +    if (ret < 0)
> +        goto error;

This will cause it to leak all other resources in case Push/Pop fails 
for some reason, which is very much not ideal.

I'd probably just leave all CUDA calls unchecked here. Or check them, 
but ignore the result and just go on anyway.
Nothing sensible to be done when stuff fails on uninit anyway.

>       ctx->cudl = NULL;
>   
>       av_buffer_unref(&ctx->hwframe);
> @@ -693,6 +705,9 @@ static av_cold int cuvid_decode_end(AVCodecContext *avctx)
>       cuvid_free_functions(&ctx->cvdl);
>   
>       return 0;
> +
> +error:
> +    return ret;
>   }
>   
>   static int cuvid_test_capabilities(AVCodecContext *avctx,
>