Intermittent hang/busy X server on X Server exit

[toddcrom3]

Hello,

I have been having an intermittent but mostly present problem with the X server on the Raspberry Pi hanging on exit. If all I do is type xinit, with no .xinitrc in place hence I get the single xterm with no window manager running, then move the pointer to focus on that window, then type exit, either I will get back to the console screen and everything is fine, or most of the time, the X Server will not fully exit, and the screen will be black, with no amount of keypresses, ^C, ^\, attempted sys-req, attempted ctrl-alt-backspace, or anything causing any effect.

If I have ssh’ed in from another place, I can see the X Server is chewing up 100 percent (well, 98 or more) of the CPU, and it is unresponsive to kill -9 (!), and if I attempt to attach to it with gdb –p, gdb hangs too before doing anything useful. Strace shows no activity, so presumably when it hangs it is in a very tight loop with no system calls. The only useful log message has an error about FBIOBLANK: Operation not permitted. I tried putting the hotplug and drive lines in my config.txt but no change. Sometimes but not always, the first time I exit from the X Server, it works, but the second time almost always hangs on exit. Fbdev is 0.4.2-6, and the xorg-server is 1.12.2-1. The system is up to date from pacman.

Q: Anyone else seeing this X Server hang?
Q: Any good ideas on easy ways to debug the hang or things to try?

I am happy to try to build the X Server and binary search with time-honored printf debugging to find the problem, but regarding that:

Q: I downloaded the xorg-server-devel, and all that is are header files. Where is the source that corresponds to xorg-server? It might be xorg-server-xdmx, or xorg-server-xfvb, or neither of those.

[captain]

I've had a similar problem.
After installing lxde, I was able to start the session when loggin in via SSH and lxsession.
Was working fine as well but I wasn't able to logout and when I forced quit the x session in the terminal it gave me an error about not being able to close the x server...
After this I have to cut the power to the Pi as it is totally unresponsive, except for giving me a password prompt when logging in via SSH - although the login never finishes.
A parallel SSH session is unresponsive as well...

[toddcrom3]

Password prompt then login never finishes on new ssh attempt, that matches my experience. Parallel ssh session unresponsive, similar -- when I do this I sometimes get some ability to do stuff, but direct attempts to attach to the busy X Server process are generally unsuccessful, and after a short time my abilities to do anything with the RPi come to a standstill, and then power off, like you do, is the only antidote.

[captain]

Well, this doesn't look so well. I'm not even too hung up on this as I'd only use it for vnc purposes when I'm too lazy to use the commandline. Starting/Quitting GUIs after SSH -X never gave me any trouble - have you tried that?
Also, if you find a fix, please post it here

[devacc12]

I have the same problem on the RPi.
Often seems OK when running startx from root but when I run from a different account I alway get a blank screen on exiting and cannot get a console or ssh session to find out what's going on.
The only recourse I have currently is to power off/on.

[pepedog]

I have this also.
Fix is on it's way
https://github.com/raspberrypi/linux/co ... pi-patches
Next kernel update will include. It's only a temporary fix