NM crashing with error: Display failure detected on display

[jbearyman]

I am using a 7.2.3 client on Windows 10 with a 6.0.66 server hosted on Linux (RHEL 7).  Initially when I bring up displays on NM everything works fine, but when I select to bring up a sub-display, NM crashes with the error: Session: Display failure detected on display ‘nx/nx, options=/usr/NX/var/log/node/xxx/options:1001’.

NXTRACE.LOG:

Module: C:\Program Files (x86)\NoMachine Enterprise Client\bin\nxclient.bin pid 912

Thread: 8200 exception 0xc0000005, ‘Access violation’

In: C:\Program Files (x86)\NoMachine Enterprise Client\bin\libnxdifb.dll at 0x69a5220c

Error: Invalid read from address 0x130cd000

#0 0x69a5220c libnxdifb.dll(fbBlt)
#1 0x746d7630 msvcrt.dll(realloc)
#2 0x695e531c libpixman.dll(pixman_region_rectangles)
#3 0x7760cf59 ntdll.dll(RtlAllocateHeap)
#4 0x69a5eb5e libnxdifb.dll(fbCopyWindowProc)
#5 0x77635e97 ntdll.dll(RtlGetAppContainerNamedObjectPath)
#6 0x7765ae7d ntdll.dll(RtlCaptureContext)

Initially, I thought this was because the server version and client were mismatch, but I get the same results with the server at 7.2.3.  One other thing to note, if I run a client (nxplayer) on Linux everything works fine.

[Carin]

Hi jbearyman,

Are you running a custom, floating window(rootless) session?
Can you further clarify what you mean by this “when I select to bring up a sub-display”?
Thanks!

 

[jbearyman]

Yes, it is rootless. From my display I can select a menu option that pops up another window for manual data entry. NoMachine crashes when it is trying to render that window.

[jbearyman]

Ran a couple other times and got these results in nxtrace.log after crash:
#0 0x69a5220c libnxdifb.dll(fbBlt)
#1 0x695e4c34 libpixman.dll(pixman_image_create_radial_gradient)
#2 0x69a5eb5e libnxdifb.dll(fbCopyWindowProc)
#3 0x69b61adf libnxdifb.dll(miCopyRegion)

This is different from the original nxtrace but seems to be more common.

[graywolf]

Hello. Is it a well know application? I’d like to reproduce that problem.

[jbearyman]

Hello,

We figured out the issue. We had a window that was being placed at position 0,0 of the monitor instead of within the parent NoMachine frame. I am guessing when NoMachine was attempting to render that window it could not interpret the correct location to place the window and crashed. What is interesting is that running the same code on a 6.0.66 Windows client does not crash NM. I wonder if this was something that was broken/fixed in the 7 version.

[graywolf]

Windows placed at 0,0 should not cause any harm. It is a valid position for a window like any other. Have you got any sample program to reproduce such problem? Or would you name the software you are using? If it is in-house software, would you tell me which graphical library it is built on?
You could send such information to forum (at) nomachine.com if you prefer.

[Author]

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