Kurento eats 100% of CPU and becomes unresponsive in RTP receiver scenario

[makkarpov]

Prerequisites

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• I have read the Troubleshooting Guide and Support Instructions.

Issue description

We have simple RTP-to-WebRTC broadcast scenario with One-to-Many Dispatcher in the middle, like this:

Now, if I go to the browser and hit F5 couple of times (each time letting Kurento fully create new port and WebRTC endpoint and complete WebRTC negotiation, so picture appears), it becomes unresponsive very soon. I encountered this on 20th refresh. When this happens, Kurento eats all available CPU cores. It can recover automatically in tenth of seconds, or it can stay in this state for a tenth of minutes. The general trend is that more aggressive refreshes lead to longer outage times.

Both RTP source and negotiated WebRTC codecs are H.264, so Kurento does not transcode here, it just acting as a packet forwarder.

How to reproduce?

Create pipeline as on picture and add WebRTC receivers to it.

Expected & current behavior

Does not hang & hangs.

About Kurento Media Server

• Kurento version: 6.16.0, docker sha256:63c5a7f5e0bab4dafd2d846fd729093763dc3e4ccaa9bbd4dab3cd0bafbad51e
• Server OS: Fedora 33
• Installation method:
  • Docker

About your Application Server

• Programming Language: Custom-made JSON-RPC client based on Akka actors
• Kurento Client version: N/A

About end-user clients

• Device(s): PC
• OS(es): Fedora 33 (different machine than server)
• Browser(s): Chrome 88

Run these commands

Ubuntu 16.04.7 LTS

Kurento Media Server version: 6.16.0
Found modules:
	'chroma' version 6.16.0
	'core' version 6.16.0
	'crowddetector' version 6.16.0
	'elements' version 6.16.0
	'filters' version 6.16.0
	'platedetector' version 6.16.0
	'pointerdetector' version 6.16.0

DPKG package list

ii  gstreamer1.5-alsa:amd64              1.8.1-1kurento2.16.04                    amd64        GStreamer plugin for ALSA
ii  gstreamer1.5-libav:amd64             1.8.1-1kurento1.16.04                    amd64        libav plugin for GStreamer
ii  gstreamer1.5-libav-dbg:amd64         1.8.1-1kurento1.16.04                    amd64        libav plugin for GStreamer (debug symbols)
ii  gstreamer1.5-nice:amd64              0.1.18-0kurento1.16.04                   amd64        ICE library (GStreamer 1.5 plugin)
ii  gstreamer1.5-nice-dbgsym:amd64       0.1.18-0kurento1.16.04                   amd64        debug symbols for package gstreamer1.5-nice
ii  gstreamer1.5-plugins-bad:amd64       1.8.1-1kurento5.16.04                    amd64        GStreamer plugins from the "bad" set
ii  gstreamer1.5-plugins-bad-dbg:amd64   1.8.1-1kurento5.16.04                    amd64        GStreamer plugins from the "bad" set (debug symbols)
ii  gstreamer1.5-plugins-base:amd64      1.8.1-1kurento2.16.04                    amd64        GStreamer plugins from the "base" set
ii  gstreamer1.5-plugins-base-dbg:amd64  1.8.1-1kurento2.16.04                    amd64        GStreamer plugins from the "base" set
ii  gstreamer1.5-plugins-good:amd64      1.8.1-1kurento5.16.04                    amd64        GStreamer plugins from the "good" set
ii  gstreamer1.5-plugins-good-dbg:amd64  1.8.1-1kurento5.16.04                    amd64        GStreamer plugins from the "good" set
ii  gstreamer1.5-plugins-ugly:amd64      1.8.1-1kurento1.16.04                    amd64        GStreamer plugins from the "ugly" set
ii  gstreamer1.5-plugins-ugly-dbg:amd64  1.8.1-1kurento1.16.04                    amd64        GStreamer plugins from the "ugly" set (debug symbols)
ii  gstreamer1.5-pulseaudio:amd64        1.8.1-1kurento5.16.04                    amd64        GStreamer plugin for PulseAudio
ii  gstreamer1.5-x:amd64                 1.8.1-1kurento2.16.04                    amd64        GStreamer plugins for X11 and Pango
ii  kms-chroma                           6.16.0-0kurento1.16.04                   amd64        Kurento Chroma filter
ii  kms-core                             6.16.0-0kurento1.16.04                   amd64        Kurento Core module
ii  kms-core-dbg                         6.16.0-0kurento1.16.04                   amd64        Kurento Core module
ii  kms-crowddetector                    6.16.0-0kurento1.16.04                   amd64        Kurento Crowd Detector filter
ii  kms-elements                         6.16.0-0kurento1.16.04                   amd64        Kurento Elements module
ii  kms-elements-dbg                     6.16.0-0kurento1.16.04                   amd64        Kurento Elements module
ii  kms-filters                          6.16.0-0kurento1.16.04                   amd64        Kurento Filters module
ii  kms-filters-dbg                      6.16.0-0kurento1.16.04                   amd64        Kurento Filters module
ii  kms-jsonrpc                          6.16.0-0kurento1.16.04                   amd64        Kurento JSON-RPC library
ii  kms-jsonrpc-dbg                      6.16.0-0kurento1.16.04                   amd64        Kurento JSON-RPC library
ii  kms-platedetector                    6.16.0-0kurento1.16.04                   amd64        Kurento Plate Detector filter
ii  kms-pointerdetector                  6.16.0-0kurento1.16.04                   amd64        Kurento Pointer Detector filter
ii  kmsjsoncpp                           1.6.3-1kurento1.16.04                    amd64        Kurento jsoncpp library
ii  kmsjsoncpp-dbg                       1.6.3-1kurento1.16.04                    amd64        Kurento jsoncpp library
ii  kurento-dbg                          6.16.0-0kurento1.16.04                   amd64        Meta-package that installs debug symbols
ii  kurento-media-server                 6.16.0-0kurento1.16.04                   amd64        Kurento Media Server
ii  kurento-media-server-dbg             6.16.0-0kurento1.16.04                   amd64        Kurento Media Server
ii  libgstreamer-plugins-bad1.5-0:amd64  1.8.1-1kurento5.16.04                    amd64        GStreamer development files for libraries from the "bad" set
ii  libgstreamer-plugins-base1.5-0:amd64 1.8.1-1kurento2.16.04                    amd64        GStreamer libraries from the "base" set
ii  libgstreamer1.5-0:amd64              1.8.1-1kurento2.16.04                    amd64        Core GStreamer libraries and elements
ii  libgstreamer1.5-0-dbg:amd64          1.8.1-1kurento2.16.04                    amd64        Core GStreamer libraries and elements
ii  libnice10:amd64                      0.1.18-0kurento1.16.04                   amd64        ICE library (shared library)
ii  libnice10-dbgsym:amd64               0.1.18-0kurento1.16.04                   amd64        debug symbols for package libnice10
ii  libsrtp0:amd64                       1.6.0-0kurento1.16.04                    amd64        Secure RTP (SRTP) and UST Reference Implementations - shared library
ii  libusrsctp                           0.9.2-1kurento1.16.04                    amd64        sctp-refimpl library
ii  openh264                             1.5.0-0kurento1.16.04                    amd64        H.264 Video Codec provided by Cisco Systems, Inc.
ii  openh264-gst-plugins-bad-1.5:amd64   1.8.1-1kurento5.16.04                    amd64        GStreamer plugins from openh264
ii  openwebrtc-gst-plugins               0.10.0-1kurento1.16.04                   amd64        OpenWebRTC specific GStreamer plugins
ii  openwebrtc-gst-plugins-dbg           0.10.0-1kurento1.16.04                   amd64        OpenWebRTC specific GStreamer plugins

[github-actions]

Hello @makkarpov! 👋 we're sorry you found a bug... so first of all, thank you very much for reporting it.

To know about progress, check in Triage. All issues are considered Backlog Candidates until work priorities align and the issue is selected for development. It will then become part of our official Backlog.