NoMachine crashes my session on the server?

[joseph.riad]

My setup:

Client: Mac OS 10.13.4 (High Sierra)

Server: Debian 9.4 (Stretch)

I’ve been having intermittent crash issues where the behavior is as follows:

1. My session stops accepting mouse and keyboard input
2. Applications stop responding
3. Eventually the screen goes blank and I’m taken back to my log in screen (Debian log in not nomachine log in) so it seems that my graphical session crashes.

This behavior is seemingly random and occurs from time to time without me changing anything about the connection. Today, I read that sometimes crashes may be caused by UDP traffic handling and the workaround is to disable UDP altogether. When I did that and tried reconnecting, the remote session immediately crashed and logged me out (again, logged me out on the remote OS, the NX session was still connected). I’m able to reproduce this behavior by disconnecting from the NX connection, opening the connection settings on the client side (without necessarily changing any settings) and re-connecting. The issue seems independent of whether I have UDP enabled.

Has anyone faced a similar issue and found a fix?

[fra81]

Hi,

it looks like a crash of the X server. I’d start with checking X server’s logs, typically ‘/var/log/Xorg.0.log.old’, but to be sure you can grab any file starting with “Xorg.” in /var/log. You can attach the files here or send to forum[at]nomachine[dot]com. You may also try to update your system.

[joseph.riad]

Hi fra81,

You’re absolutely right. Here’s the relevant part of the log, which seems to indicate that the X server segfaults:

[2308399.143] (EE)

[2308399.143] (EE) Backtrace:

[2308399.143] (EE) 0: /usr/lib/xorg/Xorg (xorg_backtrace+0x4a) [0x55b86429b65a]

[2308399.143] (EE) 1: /usr/lib/xorg/Xorg (0x55b8640e2000+0x1bd3e9) [0x55b86429f3e9]

[2308399.143] (EE) 2: /lib/x86_64-linux-gnu/libpthread.so.0 (0x7f1151dae000+0x110c0) [0x7f1151dbf0c0]

[2308399.143] (EE) 3: /usr/lib/xorg/modules/drivers/modesetting_drv.so (0x7f114db38000+0xc0c1) [0x7f114db440c1]

[2308399.143] (EE) 4: /usr/lib/xorg/Xorg (0x55b8640e2000+0xce555) [0x55b8641b0555]

[2308399.143] (EE) 5: /usr/lib/xorg/Xorg (0x55b8640e2000+0xd9242) [0x55b8641bb242]

[2308399.143] (EE) 6: /usr/lib/xorg/Xorg (0x55b8640e2000+0x1a4b63) [0x55b864286b63]

[2308399.143] (EE) 7: /usr/lib/xorg/Xorg (miPointerSetPosition+0x194) [0x55b864287964]

[2308399.143] (EE) 8: /usr/lib/xorg/Xorg (0x55b8640e2000+0x6ad0e) [0x55b86414cd0e]

[2308399.143] (EE) 9: /usr/lib/xorg/Xorg (0x55b8640e2000+0x6b513) [0x55b86414d513]

[2308399.143] (EE) 10: /usr/lib/xorg/Xorg (GetPointerEvents+0xef) [0x55b86414edbf]

[2308399.143] (EE) 11: /usr/lib/xorg/Xorg (0x55b8640e2000+0xf152e) [0x55b8641d352e]

[2308399.143] (EE) 12: /usr/lib/xorg/Xorg (0x55b8640e2000+0x54725) [0x55b864136725]

[2308399.143] (EE) 13: /usr/lib/xorg/Xorg (0x55b8640e2000+0x586a8) [0x55b86413a6a8]

[2308399.143] (EE) 14: /lib/x86_64-linux-gnu/libc.so.6 (__libc_start_main+0xf1) [0x7f1151a2f2e1]

[2308399.143] (EE) 15: /usr/lib/xorg/Xorg (_start+0x2a) [0x55b86412433a]

[2308399.143] (EE)

[2308399.143] (EE) Segmentation fault at address 0x0

[2308399.143] (EE)

Fatal server error:

[2308399.143] (EE) Caught signal 11 (Segmentation fault). Server aborting

[2308399.143] (EE)

[2308399.143] (EE)

Please consult the The X.Org Foundation support

at http://wiki.x.org

for help.

[2308399.143] (EE) Please also check the log file at “/var/log/Xorg.0.log” for additional information.

[2308399.143] (EE)

[2308399.143] (II) AIGLX: Suspending AIGLX clients for VT switch

[2308399.194] (EE) Server terminated with error (1). Closing log file.

I will see if I can file a bug with this information because (as far as I know), both my OS’s are up-to-date (unless you meant to upgrade to Debian unstable).

[fra81]

This looks like the same issue reported in https://forums.nomachine.com/topic/lock-the-physical-screen-when-somebody-connects-session-disappears#post-18075. It seems that the bug upstream is still open.

To work around the issue, you can try to unselect ‘Lock the physical screen when somebody connects’.

[Author]

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