openjdk 11 crash with SIGSEGV (0xb) at pc=0x00007f879bce3ec8, pid=9190, tid=9262 using opencv 4.5.1 on ubuntu 20.04

[Pietro Cristofanilli]

I'm creating a sprin boot application that use opncv to read read n cams using rstp protocol an send images to am angular frontend.
After a few the java application died with this error:

    #
    # A fatal error has been detected by the Java Runtime Environment:
    #
    # SIGSEGV (0xb) at pc=0x00007f879bce3ec8, pid=9190, tid=9262
    #
    # JRE version: OpenJDK Runtime Environment (11.0.11+9) (build 11.0.11+9-Ubuntu-0ubuntu2.20.04)
    # Java VM: OpenJDK 64-Bit Server VM (11.0.11+9-Ubuntu-0ubuntu2.20.04, mixed mode, sharing, tiered, compressed oops, g1 gc, linux-amd64)
    # Problematic frame:
    # C [libc.so.6+0xbeec8]
    #
    # Core dump will be written. Default location: Core dumps may be processed with "/usr/share/apport/apport %p %s %c %d %P %E" (or dumping to /home/pietro/data/passportWS/opencv-facedetection-master/core.9190)
    #
    # An error report file with more information is saved as:
    # /home/pietro/data/passportWS/opencv-facedetection-master/hs_err_pid9190.log
    #
    # If you would like to submit a bug report, please visit:
    # https://bugs.launchpad.net/ubuntu/+source/openjdk-lts
    # The crash happened outside the Java Virtual Machine in native code.
    # See problematic frame for where to report the bug.
    #
the code is above

    @Slf4j
    public class WebCamService {
 public WebCamService(WebCam camData) {
  cam.setName(camData.getName());
  String url;
  if ( Strings.allHaveText(camData.getLogin(), camData.getPassword() ) ) {
   url = String.format( CREDENTIAL_URL_TEMPLATE, Utils.getUrlProtocol( camData.getUrl() ),camData.getLogin(), camData.getPassword(), Utils.getUrlAddress( camData.getUrl() ) );
  } else {
   url = camData.getUrl();
  }
  cam.setHost( url );
  this.id = camData.getId();

  if ( Strings.hasText( camData.getSilhouettes() ) ) {
   types = Arrays.asList( camData.getSilhouettes().split(",") );
  } else {
   types = new ArrayList<String>();
  }
 }

 private static final String CREDENTIAL_URL_TEMPLATE = "%s://%s:%s@%s";
 private static final String TOPIC_TEMPLATE = "/topic/%s%s";
 private static final String IMG_VIDEO_TEMPLATE = "%s/%s";

 private List<String> types;

 @Autowired
    private SimpMessagingTemplate template;

    @Autowired
    private NeuralProcessor neuralProcessor;
 private WebCamViewer cam = new WebCamViewer();

 private ExecutorService read;

 private ExecutorService work;

 @Value("${video.dir.path}")
 private String videoDirPath;

 @Value("${image.dir.path}")
 private String imageDirPath;

 private AtomicBoolean screenshot = new AtomicBoolean(false);

 private Long id;

 public Long getId() {
  return id;
 }

 public void setId(Long id) {
  this.id = id;
 }

 public boolean startCam() {
  cam.open();

  if (!cam.isOpened()) {
   log.error("Error opening video camera {}", cam.getName() );
  } else {
   read = Executors.newSingleThreadExecutor();
   work = Executors.newSingleThreadExecutor();
   String streamTopic = String.format( TOPIC_TEMPLATE, "", getId() );
   String screenTopic = String.format( TOPIC_TEMPLATE, "screen_", getId() );

   log.info("Video camera {} is opened", cam.getName() );

   Object _self = this;

   AtomicReference<Mat> atomicFrame = new AtomicReference<Mat>();
   read.execute(() -> {
    Mat f = new Mat();
    int idx = 0;
    while (!read.isShutdown() && cam.isOpened()) {

     synchronized (_self) {
      f.release();
      if ( cam.read(f) ) {
       atomicFrame.set(f);
      }
     }

    }
   });
   work.execute(() -> {
    int counter = 0;
    int err = 0;
    Mat f = new Mat();
    List<DnnObject> objs = new ArrayList<DnnObject>();
    while (!work.isShutdown() && cam.isOpened()) {
     Mat frame = null;
     synchronized (_self) {
      frame = atomicFrame.get();
      if ( frame != null ) {
       frame.copyTo(f);
       frame = f;
      }
     }

     if (frame != null) {
      if (frame.empty()) {
       err++;
      } else {
       err = 0;
       if (++counter % 15 == 0) {
        counter = 0;
        neuralProcessor.getObjectsInFrame(objs,frame, false, types);
       }
       if ( screenshot.get() ) {
        try {
         if ( Utils.saveImage( frame, Utils.generateFilename( String.format(IMG_VIDEO_TEMPLATE, imageDirPath, cam.getName() ), "jpg" ) ) ) {
          this.template.convertAndSend( screenTopic, Utils.getBase64( frame ) );
          screenshot.set(false);
         }
        } catch (MessagingException e) {
         log.error("Error sending topic of screenshoot {}", e);
        } catch (IOException e) {
         log.error("Error sending topic of screenshoot {}", e);
        }
       }
       final Mat f1 = frame;
       objs.forEach(obj -> Imgproc.rectangle(f1, obj.getRightTop(), obj.getLeftBottom(), new Scalar(255, 255, 0) ) );
          try {
        this.template.convertAndSend(streamTopic, Utils.getBase64(frame));
       } catch (MessagingException e) {
        log.error("Error sending topic {}", e);
       } catch (IOException e) {
        log.error("Error sending topic {}", e);
       }
      }
      frame.release();
      if (err >= 10) {
       stopCam();
      }
     }
    }
   });
  }
  return cam.isOpened();
 }

 public boolean stopCam() {
  stopRecording();
  if ( read != null && !read.isTerminated() ) {
   read.shutdown();
  }
  if ( work != null && !work.isTerminated() ) {
   work.shutdown();
  }
  cam.close();
  return !cam.isOpened();
 }
 public void takeScreenshot() {
  if ( cam.isOpened() ) {
   screenshot.set( true );
  }
 }

 public boolean isOn() {
  return cam.isOpened();
 }
    }

where WebCamViewer is a simple wrapper of VideoCapture.

In the spring-boot starter class there is an executor that every 30 seconds call

    System.runFinalization();
 System.gc();

I'd appreciate any advice or direction on how to solve this, thanks

full statck trace here https://drive.google.com/file/d/114FV0dZ3a_nXIYUrR8SBrXp-lBwuPojd/view?usp=sharing

[Vladimir Petko (vpa1977)]

Hi, sorry for the late reply, is it still an issue with 11.0.20+8?

[Launchpad Janitor (janitor)]

[Expired for openjdk-lts (Ubuntu) because there has been no activity for 60 days.]