"Lock the physical screen when somebody connects" session disappears

[saips]

Hi,

Quick facts:

• Linux Mint 17.3, cinnamon
• NoMachine free, linux server, version 6.0.78
• Windows 10 player, version 6.0.80

Whenever I use NoMachine and disconnect (either by network failure or by closing the player), the cinnamon session gets completely destroyed.

When I reconnect or come into the office the next day, I’m on the login screen and all open programs are closed.

Needless to say, it’s a pain.

 

I got the problem in the past and recently re-installed NoMachine on my to see if it helps.
It was working fine until I checked the “Lock the physical screen when somebody connects” checkbox, so the problem seems to be around this area.

While connected, everything works fine and the physical screen is locked properly. It seems that an error happens when this lock gets removed, which then destroys the whole session.

 

/usr/NX/var/log/nxerror.log says:

Info: Handler started with pid 5664 on Mon Feb 26 18:45:11 2018.

Info: Handling connection from 198.18.255.130 port 45812 on Mon Feb 26 18:45:11 2018.

Info: Connection from 198.18.255.130 port 45812 closed on Mon Feb 26 18:45:23 2018.

Info: Handler with pid 5664 terminated on Mon Feb 26 18:45:23 2018.

Connection failure: Connection refused

pa_context_connect() failed: Connection refused

Connection failure: Connection refused

pa_context_connect() failed: Connection refused

Error: Session with pid ‘5148’ terminated unexpectedly.

5266 5266 18:45:45 841.234 Io/Io: WARNING! Can’t find pid monitor for 5148.

Failure: No such entity

Failure: No such entity

Error: Cannot connect to NoMachine monitor.

6473 6473 18:46:21 555.795 Io/Io: WARNING! Can’t find pid monitor for 5883.

Info: Handler started with pid 8082 on Mon Feb 26 19:00:29 2018.

Info: Handling connection from 198.18.255.130 port 45862 on Mon Feb 26 19:00:29 2018.

Info: Connection from 198.18.255.130 port 45862 closed on Mon Feb 26 19:00:36 2018.

Info: Handler with pid 8082 terminated on Mon Feb 26 19:00:36 2018.

Connection failure: Connection refused

pa_context_connect() failed: Connection refused

Connection failure: Connection refused

pa_context_connect() failed: Connection refused

Error: Session with pid ‘7722’ terminated unexpectedly.

 

This log doesn’t give away much. Where should I search further?

I also got a full server log available, if required.

 

Thankful for any help..

[Britgirl]

We aren’t able to reproduce this problem at all.

Are there any .xsession-errors in the Home directory?

By all means send in the logs that you have, you can either attach them here or submit them to forum[at]nomachine[dot]com.

[saips]

Thank you, I’ve just sent over the logs.

This issue did not exist when I first installed NoMachine on that desktop ~2 years ago, so I’m not sure if/which package or software update might have caused it.

[kroy]

Thanks for the logs but they didn’t show anything unusual that might point to a problem with lock screen. Can you send also Xorg logs?

sudo tar zcf xorglogs.tar.gz /var/log/Xorg*

[saips]

Hi kroy,

I deleted the logfiles before reproducing, so there’s only 1 file (Xorg.0.log). Nothing pops up there, so I searched a bit further…

There’s logs in /var/log/mdm which contained errors (attached as var-log-mdm.tar.zg),

“Segmentation fault at address 0x28”

and as some other guys on the web, I also have an intel (i7-6700k) with onboard graphics (HD530 iirc)

So I’m no longer sure that NoMachine can help me with this issue.

However, I don’t have any other issues whatsoever, only when using NoMachine and reconnecting after a session with “lock physical screen” checked.

Maybe it’s worth mentioning that I have the option to resize client resolution checked and both 2 screens are set at 1920×1080 – the same as the physical screens at work and at home.

 

Any ideas?

Attachments:

1. var-log-mdm.tar.gz

[saips]

So I updated to Mint 18.3 today incl. new xorg versions, but the issue is still there:

X.Org X Server 1.18.4

xorg-server 2:1.18.4-0ubuntu0.7

xserver-xorg-video-intel (2:2.99.917+git20160325-1ubuntu1.2)

inxi -G:

Graphics:  Card: Intel Sky Lake Integrated Graphics

Display Server: X.Org 1.18.4 drivers: intel (unloaded: fbdev,vesa)

Resolution: 1920×1080@60.00hz, 1920×1080@60.00hz

GLX Renderer: Mesa DRI Intel HD Graphics 530 (Skylake GT2)

GLX Version: 3.0 Mesa 17.2.8

 

and the same error:

(EE) Backtrace:

(EE) 0: /usr/lib/xorg/Xorg (xorg_backtrace+0x4e) [0x5628b1ac36ce]

(EE) 1: /usr/lib/xorg/Xorg (0x5628b1911000+0x1b6a69) [0x5628b1ac7a69]

(EE) 2: /lib/x86_64-linux-gnu/libc.so.6 (0x7f84d5def000+0x354b0) [0x7f84d5e244b0]

(EE) 3: /usr/lib/xorg/Xorg (0x5628b1911000+0x5afeb) [0x5628b196bfeb]

(EE) 4: /usr/lib/xorg/Xorg (0x5628b1911000+0x644e7) [0x5628b19754e7]

(EE) 5: /usr/lib/xorg/Xorg (0x5628b1911000+0x14bb32) [0x5628b1a5cb32]

(EE) 6: /usr/lib/xorg/Xorg (0x5628b1911000+0x53d9f) [0x5628b1964d9f]

(EE) 7: /usr/lib/xorg/Xorg (0x5628b1911000+0x57e13) [0x5628b1968e13]

(EE) 8: /lib/x86_64-linux-gnu/libc.so.6 (__libc_start_main+0xf0) [0x7f84d5e0f830]

(EE) 9: /usr/lib/xorg/Xorg (_start+0x29) [0x5628b1953069]

(EE)

(EE) Segmentation fault at address 0x28

(EE)

Fatal server error:

(EE) Caught signal 11 (Segmentation fault). Server aborting

 

 

I removed ‘xserver-xorg-video-intel’ and “inxi -G” now shows:

Graphics:  Card: Intel Sky Lake Integrated Graphics

Display Server: X.Org 1.18.4 drivers: (unloaded: fbdev,vesa)

Resolution: 1920×1080@60.00hz, 1920×1080@60.00hz

GLX Renderer: Mesa DRI Intel HD Graphics 530 (Skylake GT2)

GLX Version: 3.0 Mesa 17.2.8

but the issue still exists. Also tried creating a config in /etc/X11/xorg.conf.d/20-intel.conf with the following content to use uxa:

Section “Device”

Identifier  “Intel Graphics”

Driver      “intel”

Option      “AccelMethod”  “uxa”

Option      “TearFree”     “true”

EndSection

 

Mint then shows a warning that it’s running in software rendering mode, but that also did not solve it and I still get the same seg fault.

[Britgirl]

From the log extracts it seems to be an X.org problem rather than a NoMachine problem. If you can send us some complete backtraces from X.org we can try to help you with debugging by taking a look at them. There is a useful guide with tips on debugging the Xserver on X.org Foundation website: https://www.x.org/wiki/Development/Documentation/ServerDebugging/

[saips]

Thanks Britgirl and sorry for the delay. Finally found time to dig deeper.

Here’s what I got as soon as I closed the NoMachine player:

Thread 1 “Xorg” received signal SIGSEGV, Segmentation fault.

0x0000556d576b8feb in DeviceFocusEvents (mode=2, to=0x1, from=0x556d58a20270,

dev=0x556d58c5a970) at ../../dix/enterleave.c:1462

1462    ../../dix/enterleave.c: No such file or directory.

 

The stacktrace of gdb’s “bt f” is attached. Anything else I can do?

Attachments:

1. gdb.txt

[danny]

I also encounter this problem, but in a slightly different way. When I activate “EnableScreenLock 1” in /usr/NX/etc/server.cfg, which should be equivalent to “Lock the physical screen when somebody connects”, I will see that my X server got restarted when I log in to nomachine. The different with the original post is that I saw the restart happening when I log in to nomachine session, not when I disconnect. This does not happen everytime, but on enough occassions to annoy users. When i disable “EnableScreenLock”, the problem goes away.

Please take a look at this problem because the “EnableScreenLock” is an important security feature for my setup.

I am using Ubuntu 16.04, NoMachine version 6.0.78 (I also observe the problem in 6.0.66).

Unfortunately i could not run the gdb on Xorg because of some missing packages.

This is what I see in /var/log/Xorg.log.old:

/var/log/Xorg.log.old:

[ 62405.430] (EE) Backtrace:
[ 62405.430] (EE) 0: /usr/lib/xorg/Xorg (xorg_backtrace+0x4e) [0x56540b73fa9e]
[ 62405.430] (EE) 1: /usr/lib/xorg/Xorg (0x56540b58e000+0x1b57f9) [0x56540b7437f9]
[ 62405.430] (EE) 2: /lib/x86_64-linux-gnu/libpthread.so.0 (0x7f71f4761000+0x11390) [0x7f71f4772390]
[ 62405.430] (EE) 3: /usr/lib/xorg/modules/drivers/modesetting_drv.so (0x7f71f0902000+0xc131) [0x7f71f090e131]
[ 62405.430] (EE) 4: /usr/lib/xorg/Xorg (0x56540b58e000+0xccf03) [0x56540b65af03]
[ 62405.430] (EE) 5: /usr/lib/xorg/Xorg (0x56540b58e000+0xd7df2) [0x56540b665df2]
[ 62405.430] (EE) 6: /usr/lib/xorg/Xorg (0x56540b58e000+0x19d0c3) [0x56540b72b0c3]
[ 62405.430] (EE) 7: /usr/lib/xorg/Xorg (miPointerSetPosition+0x19c) [0x56540b72becc]
[ 62405.430] (EE) 8: /usr/lib/xorg/Xorg (0x56540b58e000+0x6a91e) [0x56540b5f891e]
[ 62405.431] (EE) 9: /usr/lib/xorg/Xorg (0x56540b58e000+0x6b115) [0x56540b5f9115]
[ 62405.431] (EE) 10: /usr/lib/xorg/Xorg (GetPointerEvents+0x124) [0x56540b5fa9e4]
[ 62405.431] (EE) 11: /usr/lib/xorg/Xorg (0x56540b58e000+0xef423) [0x56540b67d423]
[ 62405.431] (EE) 12: /usr/lib/xorg/Xorg (0x56540b58e000+0x5428b) [0x56540b5e228b]
[ 62405.431] (EE) 13: /usr/lib/xorg/Xorg (0x56540b58e000+0x583b8) [0x56540b5e63b8]
[ 62405.431] (EE) 14: /lib/x86_64-linux-gnu/libc.so.6 (__libc_start_main+0xf0) [0x7f71f43b7830]
[ 62405.431] (EE) 15: /usr/lib/xorg/Xorg (_start+0x29) [0x56540b5d0329]
[ 62405.431] (EE)
[ 62405.431] (EE) Segmentation fault at address 0x0
[ 62405.431] (EE)
Fatal server error:
[ 62405.431] (EE) Caught signal 11 (Segmentation fault). Server aborting
[ 62405.431] (EE)
[ 62405.431] (EE)
Please consult the The X.Org Foundation support
at http://wiki.x.org
for help.
[ 62405.431] (EE) Please also check the log file at “/var/log/Xorg.0.log” for additional information.
[ 62405.431] (EE)
[ 62405.431] (II) AIGLX: Suspending AIGLX clients for VT switch
[ 62405.482] (EE) Server terminated with error (1). Closing log file.

[fra81]

This looks like a different issue, and it is apparently a known bug in the modesetting driver:

https://bugzilla.redhat.com/show_bug.cgi?format=multiple&id=1487954

https://bbs.archlinux.org/viewtopic.php?id=225736

[fra81]

@saips

Can you show the output of ‘xinput’ command?

And please tell your Xorg version. Did you upgraded it recently?

• This reply was modified 6 years, 8 months ago by fra81.

[saips]

@fra81

I don’t know on which Xorg version the problem started, but after upgrading to:

X.Org X Server 1.18.4
xorg-server 2:1.18.4-0ubuntu0.7
xserver-xorg-video-intel (2:2.99.917+git20160325-1ubuntu1.2)

the problem still existed.

~ $ xinput
⎡ Virtual core pointer id=2 [master pointer (3)]
⎜ ↳ Virtual core XTEST pointer id=4 [slave pointer (2)]
⎜ ↳ PixArt Microsoft USB Optical Mouse id=11 [slave pointer (2)]
⎣ Virtual core keyboard id=3 [master keyboard (2)]
↳ Virtual core XTEST keyboard id=5 [slave keyboard (3)]
↳ Power Button id=6 [slave keyboard (3)]
↳ Video Bus id=7 [slave keyboard (3)]
↳ Power Button id=8 [slave keyboard (3)]
↳ Sleep Button id=9 [slave keyboard (3)]
↳ Microsoft Wired Keyboard 400 id=10 [slave keyboard (3)]
↳ Eee PC WMI hotkeys id=12 [slave keyboard (3)]

Also, I can confirm that the problem does not exist on fresh installations.

[danny]

Hi @fra81

Thanks to your pointer on the Xorg issue. I did a apt full-upgrade, and so far I have not seen the problem.

My Xorg version is now:

X.Org X Server 1.19.5
Release Date: 2017-10-12

Before the upgrade, my Xorg version was:

X.Org X Server 1.19.3
Release Date: 2017-03-15

[fra81]

Hi @saips,

it’s not all clear to me yet: you make a fresh system installation, then upgrade it and get the issue? Everything on the same machine? And what is the Xorg version in the fresh installation?

Also I see that you have an external keyboard and mouse. Can you check if you still reproduce the issue after unplugging them?

[fra81]

Hi @danny,

good to hear 🙂

[Author]

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