source code bug, ff_g723_1_gen_dirac_train function enters dead loop

[songtao]

Summary of the bug:
How to reproduce:
i create 5 threads to encode/decode G723_1 from different rtp session, when there's a high concurrent, it enters died loop.

pstack output, pitch_lag=0 cases the died loop

Thread 1 (Thread 0x7f70ab7fe700 (LWP 640449)):
#0  ff_g723_1_gen_dirac_train (buf=buf@entry=0x7f70ab7fc850, pitch_lag=0) at src/libavcodec/g723_1.c:1154
#1  0x0000000000642096 in get_fcb_param (optim=optim@entry=0x7f70ab7fd2b0, impulse_resp=impulse_resp@entry=0x7f70ab7fcf50, buf=buf@entry=0x7f709401d238, pulse_cnt=pulse_cnt@entry=5, pitch_lag=<optimized out>) at src/libavcodec/g723_1enc.c:840
#2  0x0000000000646489 in fcb_search (index=1, buf=0x7f709401d238, impulse_resp=0x7f70ab7fcf50, p=<optimized out>) at src/libavcodec/g723_1enc.c:1022
#3  g723_1_encode_frame (avctx=<optimized out>, avpkt=<optimized out>, frame=<optimized out>, got_packet_ptr=<optimized out>) at src/libavcodec/g723_1enc.c:1198
#4  0x00000000005ea2e1 in encode_simple_internal (avpkt=0x7f70a420c980, avctx=0x7f70a44534c0) at src/libavcodec/encode.c:214
#5  encode_simple_receive_packet (avpkt=<optimized out>, avctx=<optimized out>) at src/libavcodec/encode.c:269
#6  encode_receive_packet_internal (avctx=avctx@entry=0x7f70a44534c0, avpkt=0x7f70a420c980) at src/libavcodec/encode.c:303
#7  0x00000000005ea727 in avcodec_send_frame (avctx=avctx@entry=0x7f70a44534c0, frame=frame@entry=0x7f70a40cee00) at src/libavcodec/encode.c:380

my code, it reads 160 samples from rtp, resamples to 240 samples, then send samples to G723_1 encoder

static void encode(AVCodecContext *ctx, AVAudioFifo *fifo, AVFrame *frame,
                   AVPacket *pkt, uint8_t *out, size_t *out_size) {
  int ret;
  *out_size = 0;
  // need resample to 240
  if (fifo != NULL) {
    add_samples_to_fifo(fifo, &frame->data[0], frame->nb_samples);
    if (av_audio_fifo_size(fifo) < 240) {
      return;
    }
    // read out 240
    if (av_audio_fifo_read(fifo, (void **)&frame->data, 240) < 240) {
      log_error("Could not read data from FIFO");
      return;
    }
    frame->nb_samples = 240;
  }

  /* send the frame for encoding */
  ret = avcodec_send_frame(ctx, frame);
  if (ret < 0) {
    log_error("Error sending the frame to the encoder");
    exit(1);
  }

  /* read all the available output packets (in general there may be any
   * number of them */
  while (ret >= 0) {
    ret = avcodec_receive_packet(ctx, pkt);
    if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF) {
      return;
    } else if (ret < 0) {
      log_error("Error encoding audio frame");
      exit(1);
    }

    memcpy(out, pkt->data, pkt->size);
    *out_size = pkt->size;
    av_packet_unref(pkt);
  }
}

int ff_encoder_input(ff_encoder_ctx *ff_ctx, uint16_t *data, size_t data_size,
                     uint8_t *out, size_t *out_size) {

  int ret = av_frame_make_writable(ff_ctx->frame);
  if (ret < 0) {
    exit(1);
  }
  uint16_t *samples = (uint16_t *)ff_ctx->frame->data[0];
  memcpy(samples, data, data_size * sizeof(uint16_t));
  ff_ctx->frame->nb_samples = data_size;
  encode(ff_ctx->c, ff_ctx->fifo, ff_ctx->frame, ff_ctx->pkt, out, out_size);
  return 0;
}

% git status
HEAD detached at n5.1

Patches should be submitted to the ffmpeg-devel mailing list and not this bug tracker.