x11vnc 0.9.13 crashes in Kubuntu 18.04

[Gourmand101]

Describe the bug
The server starts from script placed in KDE autoexec folder. After this it work some time but suddenly crashes on some keyboard or mouse action.

To Reproduce

1. Place this script to ~/.kde/autoexec/x11vnc

---

#! /bin/sh
x11vnc -forever -noxfixes -noxrecord -noxdamage -remote &

2. Make it runnable
3. Reboot or restart KDE
4. Try work with it from some VNC client, for example RealVNC.
5. The server suddenly crashes and client closes window. It happiness after 1-10 minutes activity.
6. Open X-terminal window and run server with same command line as it runs from script. After this server will work stable all time you need.

Expected Behavior
The server must work stable. Previous version worked fine in Kubuntu 14.04.

Desktop:

• Linux Kubuntu 18.04 LTS, Plasma, nVidia 340.107 driver.

[bk138]

Hello! Which x11vnc version are you reffering to?

[Gourmand101]

0.9.13, sudo apt-get upgrade x11vnc tells it is latest stable version.

[bk138]

You might try with a newer release.

[Gourmand101]

Why it is not yet on public server? I do prefer upgrade from it. More than 8 months passed since release but it still not yet published for massive upgrade by apt. What is the reason? Does it contain lot of bugs?

[The-42]

Keep in mind it is up to the distribution maintainers to update a package. Not every update makes it to the repository of an OS, and especially LTS releases are not upgrade-happy. Do not expect an update on (K)Ubuntu 18.04, that is one of those long-term support versions.

[Gourmand101]

This does not depend from VNC client/viewer. The server crashes with any viewer connected after same time. I cannot show log file cause it is not created by server. I had added option

-o /var/log/x11vnc.log

to script command line. But no file with this name was created after crash.

On my workstation I develop complex projects using C++/Qt5 therefore I do not compile any other sources on it. For system purpose I use only precompiled binaries. But I cannot find precompiled 0.9.16 for Kubuntu.

[freecod]

Version 0.9.16 also crash on Kubuntu 16.04

28/12/2019 21:40:40 Got connection from client 192.168.1.58
28/12/2019 21:40:40   other clients:
28/12/2019 21:40:41 Normal socket connection
28/12/2019 21:40:41 Disabled X server key autorepeat.
28/12/2019 21:40:41   to force back on run: 'xset r on' (3 times)
28/12/2019 21:40:41 incr accepted_client=3 for 192.168.1.58:46016  sock=19
28/12/2019 21:40:41 Client Protocol Version 3.8
28/12/2019 21:40:41 Protocol version sent 3.8, using 3.8
28/12/2019 21:40:41 rfbProcessClientSecurityType: executing handler for type 2
28/12/2019 21:40:41 rfbProcessClientNormalMessage: ignoring unsupported encoding type Enc(0x00000018)
28/12/2019 21:40:41 rfbProcessClientNormalMessage: ignoring unsupported encoding type Enc(0x0000000F)
28/12/2019 21:40:41 rfbProcessClientNormalMessage: ignoring unsupported encoding type Enc(0x00000016)
28/12/2019 21:40:41 rfbProcessClientNormalMessage: ignoring unsupported encoding type Enc(0x00000015)
28/12/2019 21:40:41 rfbProcessClientNormalMessage: ignoring unsupported encoding type Enc(0xFFFFFEC6)
28/12/2019 21:40:41 Enabling full-color cursor updates for client 192.168.1.58
28/12/2019 21:40:41 Enabling NewFBSize protocol extension for client 192.168.1.58
28/12/2019 21:40:41 Using ZRLE encoding for client 192.168.1.58
28/12/2019 21:40:41 Pixel format for client 192.168.1.58:
28/12/2019 21:40:41   32 bpp, depth 24, little endian
28/12/2019 21:40:41   true colour: max r 255 g 255 b 255, shift r 16 g 8 b 0
28/12/2019 21:40:41 no translation needed
28/12/2019 21:40:42 client useCopyRect: 192.168.1.58 -1
28/12/2019 21:40:42 client_set_net: 192.168.1.58  0.0011
28/12/2019 21:40:42 created   xdamage object: 0x200043
28/12/2019 21:40:43 client 3 network rate 696.5 KB/sec (2697.2 eff KB/sec)
28/12/2019 21:40:43 client 3 latency:  9.8 ms
28/12/2019 21:40:43 dt1: 0.0184, dt2: 0.0414 dt3: 0.0098 bytes: 38277
28/12/2019 21:40:43 link_rate: LR_LAN - 9 ms, 696 KB/s
*** stack smashing detected ***: <unknown> terminated
caught signal: 6
28/12/2019 21:41:04 deleted 60 tile_row polling images.
28/12/2019 21:41:04 Restored X server key autorepeat to: 1

[Gourmand101]

After this all I removed x11vnc from autostart. Instead I added xterm to it. After system boots until ready I start x11vnc in this xterm manually. Then it works stable like a charm.

[ZedeN1]

---EDIT---
adding -noxdamage fixed the issues I was having
---EDIT---

Have the same issue when using v0.9.16 with systemd on Kubuntu 19.10.

My /lib/systemd/system/x11vnc.service file:

[Unit]
Description=Start x11vnc at startup.
After=multi-user.target

[Service]
Type=simple
ExecStart=/bin/bash -c "/usr/local/bin/x11vnc -loop -bg -forever -xkb -repeat -capslock -shared -o /var/log/x11vnc.log -auth /var/run/sddm/* -passwd **********"

[Install]
WantedBy=multi-user.target

My system info:

pavel@blackwater:~$ neofetch
            .-/+oossssoo+/-.               pavel@blackwater
        `:+ssssssssssssssssss+:`           ----------------
      -+ssssssssssssssssssyyssss+-         OS: Ubuntu 19.10 x86_64
    .ossssssssssssssssssdMMMNysssso.       Host: MS-7916 1.0
   /ssssssssssshdmmNNmmyNMMMMhssssss/      Kernel: 5.3.0-40-generic
  +ssssssssshmydMMMMMMMNddddyssssssss+     Uptime: 12 days, 21 hours, 25 mins
 /sssssssshNMMMyhhyyyyhmNMMMNhssssssss/    Packages: 4676 (dpkg), 1 (flatpak), 13 (snap)
.ssssssssdMMMNhsssssssssshNMMMdssssssss.   Shell: bash 5.0.3
+sssshhhyNMMNyssssssssssssyNMMMysssssss+   Terminal: /dev/pts/19
ossyNMMMNyMMhsssssssssssssshmmmhssssssso   CPU: Intel i5-4670K (4) @ 3.400GHz
ossyNMMMNyMMhsssssssssssssshmmmhssssssso   GPU: NVIDIA GeForce GTX 1050 Ti
+sssshhhyNMMNyssssssssssssyNMMMysssssss+   Memory: 8688MiB / 32059MiB
.ssssssssdMMMNhsssssssssshNMMMdssssssss.
 /sssssssshNMMMyhhyyyyhdNMMMNhssssssss/
  +sssssssssdmydMMMMMMMMddddyssssssss+
   /ssssssssssshdmNNNNmyNMMMMhssssss/
    .ossssssssssssssssssdMMMNysssso.
      -+sssssssssssssssssyyyssss+-
        `:+ssssssssssssssssss+:`
            .-/+oossssoo+/-.

x11vnc log file:

pavel@blackwater:~$ sudo systemctl start x11vnc.service
30/03/2020 12:04:11 passing arg to libvncserver: -passwd
30/03/2020 12:04:11 x11vnc version: 0.9.16 lastmod: 2019-01-05  pid: 22961
30/03/2020 12:04:11 XOpenDisplay("") failed.
30/03/2020 12:04:11 Trying again with XAUTHLOCALHOSTNAME=localhost ...
30/03/2020 12:04:11 ^G
30/03/2020 12:04:11 *** XOpenDisplay failed. No -display or DISPLAY.
30/03/2020 12:04:11 *** Trying ":0" in 4 seconds.  Press Ctrl-C to abort.
30/03/2020 12:04:11 *** 1 2 3 4
30/03/2020 12:04:15 *** XOpenDisplay of ":0" successful.
30/03/2020 12:04:15
30/03/2020 12:04:15 Using X display :0
30/03/2020 12:04:15 rootwin: 0x1e4 reswin: 0x3200001 dpy: 0xb36bc130
30/03/2020 12:04:15
30/03/2020 12:04:15 ------------------ USEFUL INFORMATION ------------------
30/03/2020 12:04:15 X DAMAGE available on display, using it for polling hints.
30/03/2020 12:04:15   To disable this behavior use: '-noxdamage'
30/03/2020 12:04:15
30/03/2020 12:04:15   Most compositing window managers like 'compiz' or 'beryl'
30/03/2020 12:04:15   cause X DAMAGE to fail, and so you may not see any screen
30/03/2020 12:04:15   updates via VNC.  Either disable 'compiz' (recommended) or
30/03/2020 12:04:15   supply the x11vnc '-noxdamage' command line option.
30/03/2020 12:04:15
30/03/2020 12:04:15 Wireframing: -wireframe mode is in effect for window moves.
30/03/2020 12:04:15   If this yields undesired behavior (poor response, painting
30/03/2020 12:04:15   errors, etc) it may be disabled:
30/03/2020 12:04:15    - use '-nowf' to disable wireframing completely.
30/03/2020 12:04:15    - use '-nowcr' to disable the Copy Rectangle after the
30/03/2020 12:04:15      moved window is released in the new position.
30/03/2020 12:04:15   Also see the -help entry for tuning parameters.
30/03/2020 12:04:15   You can press 3 Alt_L's (Left "Alt" key) in a row to
30/03/2020 12:04:15   repaint the screen, also see the -fixscreen option for
30/03/2020 12:04:15   periodic repaints.
30/03/2020 12:04:15
30/03/2020 12:04:15 XFIXES available on display, resetting cursor mode
30/03/2020 12:04:15   to: '-cursor most'.
30/03/2020 12:04:15   to disable this behavior use: '-cursor arrow'
30/03/2020 12:04:15   or '-noxfixes'.
30/03/2020 12:04:15 using XFIXES for cursor drawing.
30/03/2020 12:04:15 GrabServer control via XTEST.
30/03/2020 12:04:15
30/03/2020 12:04:15 Scroll Detection: -scrollcopyrect mode is in effect to
30/03/2020 12:04:15   use RECORD extension to try to detect scrolling windows
30/03/2020 12:04:15   (induced by either user keystroke or mouse input).
30/03/2020 12:04:15   If this yields undesired behavior (poor response, painting
30/03/2020 12:04:15   errors, etc) it may be disabled via: '-noscr'
30/03/2020 12:04:15   Also see the -help entry for tuning parameters.
30/03/2020 12:04:15   You can press 3 Alt_L's (Left "Alt" key) in a row to
30/03/2020 12:04:15   repaint the screen, also see the -fixscreen option for
30/03/2020 12:04:15   periodic repaints.
30/03/2020 12:04:15 X FBPM extension not supported.
30/03/2020 12:04:15 X display is capable of DPMS.
30/03/2020 12:04:15 --------------------------------------------------------
30/03/2020 12:04:15
30/03/2020 12:04:15 Default visual ID: 0x21
30/03/2020 12:04:15 Read initial data from X display into framebuffer.
30/03/2020 12:04:15 initialize_screen: fb_depth/fb_bpp/fb_Bpl 24/32/12800
30/03/2020 12:04:15
30/03/2020 12:04:15 X display :0 is 32bpp depth=24 true color
30/03/2020 12:04:15
30/03/2020 12:04:15 Autoprobing TCP port
30/03/2020 12:04:15 Autoprobing selected TCP port 5900
30/03/2020 12:04:15 Autoprobing TCP6 port
30/03/2020 12:04:15 Autoprobing selected TCP6 port 5900
30/03/2020 12:04:15 listen6: bind: Address already in use
30/03/2020 12:04:15 Not listening on IPv6 interface.
30/03/2020 12:04:15 Xinerama: Library libXinerama is not available to determine
30/03/2020 12:04:15 Xinerama: the head geometries, consider using -blackout
30/03/2020 12:04:15 Xinerama: if the screen is non-rectangular.
30/03/2020 12:04:15 fb read rate: 1608 MB/sec
30/03/2020 12:04:15 fast read: reset -wait  ms to: 10
30/03/2020 12:04:15 fast read: reset -defer ms to: 10
30/03/2020 12:04:15 The X server says there are 10 mouse buttons.
30/03/2020 12:04:15 screen setup finished.
30/03/2020 12:04:15

The VNC desktop is:      blackwater:0

******************************************************************************
Have you tried the x11vnc '-ncache' VNC client-side pixel caching feature yet?

The scheme stores pixel data offscreen on the VNC viewer side for faster
retrieval.  It should work with any VNC viewer.  Try it by running:

    x11vnc -ncache 10 ...

One can also add -ncache_cr for smooth 'copyrect' window motion.
More info: http://www.karlrunge.com/x11vnc/faq.html#faq-client-caching

30/03/2020 12:04:15 Got connection from client 10.8.0.38
30/03/2020 12:04:15   other clients:
30/03/2020 12:04:15 Normal socket connection
30/03/2020 12:04:15 incr accepted_client=1 for 10.8.0.38:56560  sock=10
30/03/2020 12:04:15 Client Protocol Version 3.8
30/03/2020 12:04:15 Protocol version sent 3.8, using 3.8
30/03/2020 12:04:15 rfbProcessClientSecurityType: executing handler for type 2
30/03/2020 12:04:15 copy_tiles: allocating first_line at size 101
30/03/2020 12:04:15 rfbProcessClientNormalMessage: ignoring unsupported encoding type Enc(0x00000018)
30/03/2020 12:04:15 rfbProcessClientNormalMessage: ignoring unsupported encoding type Enc(0x00000016)
30/03/2020 12:04:15 rfbProcessClientNormalMessage: ignoring unsupported encoding type Enc(0x00000015)
30/03/2020 12:04:15 rfbProcessClientNormalMessage: ignoring unsupported encoding type Enc(0x0000000F)
30/03/2020 12:04:15 rfbProcessClientNormalMessage: ignoring unsupported encoding type Enc(0xFFFFFEC6)
30/03/2020 12:04:15 Enabling full-color cursor updates for client 10.8.0.38
30/03/2020 12:04:15 Enabling NewFBSize protocol extension for client 10.8.0.38
30/03/2020 12:04:15 Using ZRLE encoding for client 10.8.0.38
30/03/2020 12:04:15 Pixel format for client 10.8.0.38:
30/03/2020 12:04:15   8 bpp, depth 6
30/03/2020 12:04:15   true colour: max r 3 g 3 b 3, shift r 4 g 2 b 0
30/03/2020 12:04:16 Pixel format for client 10.8.0.38:
30/03/2020 12:04:16   32 bpp, depth 24, little endian
30/03/2020 12:04:16   true colour: max r 255 g 255 b 255, shift r 16 g 8 b 0
30/03/2020 12:04:16 no translation needed
30/03/2020 12:04:17 client 1 network rate 64.4 KB/sec (1946.7 eff KB/sec)
30/03/2020 12:04:17 client 1 latency:  20.3 ms
30/03/2020 12:04:17 dt1: 0.0324, dt2: 1.9506 dt3: 0.0203 bytes: 127085
30/03/2020 12:04:17 link_rate: LR_BROADBAND - 20 ms, 64 KB/s
30/03/2020 12:04:17 client_set_net: 10.8.0.38  0.0088
30/03/2020 12:04:17 created   xdamage object: 0x3200068
30/03/2020 12:04:25 created selwin: 0x3200069
30/03/2020 12:04:25 called initialize_xfixes()
30/03/2020 12:04:53 increased wireframe timeouts for slow network connection.
30/03/2020 12:04:53 netrate: 64 KB/sec, latency: 20 ms
caught XIO error:
30/03/2020 12:06:12 deleted 100 tile_row polling images.

[Martii]

Re:

adding -noxdamage fixed the issues I was having

I think this main issue (#113), in general, is what I've been encountering since I moved from bionic (Kubuntu 18.04.x) to focal (Kubuntu 20.04.x).

My remote crashes with nothing logged that I can tell. If I connect from focal to a bionic server it's fine... but focal to focal I have to use -noxfixes which I found that solution somewhere out in the wild. The side-effect of doing this is that all cursor manipulations are almost unbearable (try resizing a window and not having the cursor change to indicate there is a grippy... guess work).

I'd really like an alternative. I've tried -noxdamage with my startup and it seems to make no difference.

Ref(s):

$ # bionic package and machines out there
$ apt-cache madison x11vnc
    x11vnc |   0.9.13-3 | http://us.archive.ubuntu.com/ubuntu bionic/universe amd64 Packages
$ uname -a
Linux remote 5.4.0-65-generic #73~18.04.1-Ubuntu SMP Tue Jan 19 09:02:24 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux

$ # focal packages and machines here
$ apt-cache madison x11vnc
    x11vnc |   0.9.16-3 | http://us.archive.ubuntu.com/ubuntu focal/universe amd64 Packages`
$ apt-cache madison tigervnc-viewer
tigervnc-viewer | 1.10.1+dfsg-3 | http://us.archive.ubuntu.com/ubuntu focal/universe amd64 Packages
$ uname -a
Linux machine 5.4.0-65-generic #73-Ubuntu SMP Mon Jan 18 17:25:17 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux

... This package combo is the fastest that I've gotten, both intranet and internet, and most configurable... so I'd like to stick with it. Distro release appears to match https://github.com/LibVNC/x11vnc/releases/tag/0.9.16 albeit it's their third build/release of it.

• x11vnc -display :0 -rfbport 5900 -rfbauth ~/.vnc/passwd -forever -noxrecord -noxfixes -repeat is how I prefer to start it (minus the noxfixes wanted; and sanitized home folder for this issue)
• loginctl lock-session is how I boot logged in via SDDM and then via KDE/Plasma startup script with screen locked.

Without -noxfixes I do see the remotes (intranet focal to focal) lock screen but then move up to that monitor and just as I'm about to type/click... boom... x11vnc crashes (so does tigervnc-viewer). I can no longer reach that remote unless I restart the machine via ssh.

Any other information is gladly given just give me a few pointers please on how to retrieve. Thanks for all of your hard work on this project. :)