X server locking up when displaying applications from another system

Question

My main display is on Gentoo, using xorg 1.15.1 (maybe I should try 1.16.0). I'm running applications in a RHEL 6.5 VM (using xorg 1.13.0). I ssh into the RHEL virtual machine, launch some heavy (java-based?) X applications that don't otherwise work on Gentoo, and get them to display on my main screen. This has the advantage of allowing the windows to move around my desktops or even integrate with my system tray.

Unfortunately, when I do this, my entire X server stops responding fairly quickly. Nothing pops out at me in the X server logs. The screens stop repainting, except for the mouse, and even the mouse eventually stops moving. This is usually within 5 to 10 minutes, but sometimes faster.

Making this worse is that my kernel can't seem to display to the console, most likely due to a combination of nvidia proprietary driver + UEFI, so hitting ctrl-alt-F1 and looking at the logs isn't an option (but I can restart X that way, losing my VM, etc., in the process). This is a different problem that isn't part of the question, only the context as to why the above is a significant issue.

I'm looking for anything I can try to get this configuration to stop locking up my X server. Restarting X every ten minutes can really impact one's productivity.

Answer 1

Try connecting to your machine from another one via ssh and monitor the whole process of starting the application remotely - watch resources like CPU, memory, swap and all appropriate logs (including the kernel ring buffer). htop and watch are your friends.

You might even be able to change to local terminal from the ssh connection by using chvt.

Run the virtual machine from a terminal multiplexer, so that you don't lose the VM when the X server goes down.

If possible, try running the VM with output to VNC (e.g. for qemu this would translate to the -vnc option), connect to it with a VNC viewer and observe whether the hangs occur in the VM as well.