X11VNC Crashing on keyboard/mouse movement

[tinng81]

Describe the bug X11VNC indicates stack smashing on mouse movement (mostly), especially on mouse click/drag and sometimes just on random keystrokes.

To Reproduce Steps to reproduce the behavior:

1. Run container + access noVNC via website or VNC viewer (I've tried both) as normal
2. Run ROS Gazebo / ROS RViz software
   • (Probably optional since I don't think it is application-related bugs)
3. Move the application's window around or leave it there after a while, lose focus of the browser/viewer and then simply click back. Or simply open File Navigator and type in any characters in the address bar.
4. noVNC will immediately disconnected

Expected behavior noVNC should not be disconnected

Versions (please complete the following information):

• OS: [Ubuntu 18.04 ARM64]
• image tag [e.g. bionic-arm64]

Additional context After quick look of the supervisor logs, I've found that the culprit is X11VNC.

x11vnc version: x11vnc: 0.9.13 lastmod: 2011-08-10 From x11vnc-stderr.log

26/08/2021 12:59:51 read X11VNC_REMOTE: cmd=fb
26/08/2021 13:00:23 read X11VNC_REMOTE: cmd=fb
26/08/2021 13:00:56 read X11VNC_REMOTE: cmd=fb
*** stack smashing detected ***: <unknown> terminated
caught signal: 6
26/08/2021 13:01:13 deleted 40 tile_row polling images.

[junhuizx]

I had met this issue. My reproduce steps:

1. start menu -> firfox
2. click firfox "open application menu" on the left top, x11vnc will crash.

[thesunofme]

do you find a way to fix it ?

[tinng81]

@thesunofme not a fix but workaround. Run x11vnc with -noxrecord flag. Worked fine for me after that.

Ref: https://github.com/LibVNC/x11vnc/issues/61#issuecomment-576402488