Bug 664353

Description of problem:

I was working on a desktop with a lot of open windows (many evince documents, many gnome-terminals etc.).  There is a known hard limit on the number of clients that an X server can support

The issue here is that if the screen lock kicks in as you cross that boundary then you will never be able to unlock the screen.   The screen flickers briefly with mouse motion or with keyboard events, but the dialog box to request your password is never presented.

The workaround is to login on another vt or via ssh and kill gnome-screensaver.

Summarizing:
If you are near the maximum number of X clients
AND you let your screen go idle with gnome-screensaver kicking in to lock the screen
THEN you may be at a situation where you can't ever unlock the screen.

Version-Release number of selected component (if applicable):

gnome-screensaver-2.30.0-2.fc13.i686


How reproducible:

yes

Steps to Reproduce:
1. move to the limit of clients to the X server (use evince on separate documents)
2. arrive at the point where one more client be over the line
3. allow the screen saver to lock the screen
4. attempt to unlock
5. see ~/.xsession-errors
  
Actual results:

$ tail ~/.xsession-errors
...trimming (this ~/.xsession-errors is 30+MB big now) ...
Maximum number of clients reached
** (/usr/libexec/gnome-screensaver-gl-helper:1371): WARNING **: Cannot open display: 
(gnome-screensaver:22765): GdkPixbuf-CRITICAL **: gdk_pixbuf_format_get_name: assertion `format != NULL' failed


Expected results:

It would be super swell if the desktop system could reserve one more connection to the X server for this residual emergency.  A popup explaining the problem and offering some sort of crude remediation (i.e. killing off something) seems indicated.  Of course there is a security concern with enabling this feature on a "locked" screensaver.


Additional info:


The workaround is "don't do that" i.e. run fewer processes, clean up those evince processes.


Separate background context that may be useful here.

https://bugs.freedesktop.org/show_bug.cgi?id=9209
Xlib: Maximum number of clients reached 
Reported:  	2006-11-30 14:32 PST by Steve Condas
Modified: 	2010-08-02 20:59 PDT (History) 


Often in a GNOME environment when one hits the limit (I've done this several times before) one gets messaging in ~/.xsession-errors reminding one of the incident.

[from a separate incident]

$ tail ~/.xsession-errors
Maximum number of clients reachedXOpenDisplay() failed
Maximum number of clients reachedFailed to parse arguments: Cannot open display: 
Maximum number of clients reachedFailed to parse arguments: Cannot open display: 
Window manager warning: last_user_time (3215845144) is greater than comparison timestamp (3168565031).  This most likely represents a buggy client sending inaccurate timestamps in messages such as _NET_ACTIVE_WINDOW.  Trying to work around...
Window manager warning: 0x1529d29 (Run Applic) appears to be one of the offending windows with a timestamp of 3215845144.  Working around...
Maximum number of clients reachedFailed to parse arguments: Cannot open display: 
Maximum number of clients reachedFailed to parse arguments: Cannot open display: