GNOME Bugzilla – Bug 570402
screensaver crash if number of screens changes
Last modified: 2011-04-27 06:28:26 UTC
Steps to reproduce: Configure a two-screen setup. I use a laptop connected to a monitor, but I suspect other configurations would work too. Activate screensaver, cause the second monitor to be removed from screen geometry, attempt to unblank. For me this is basically what happens every time I suspend the laptop to remove it from the docking station, carry it somewhere else, and resume, but it can also be triggered with a script such as gnome-screensaver-command --activate ; sleep 1 ; xrandr --output VGA --off ; sleep 3 ; gnome-screensaver-command --poke Stack trace: Sorry, can't do that -- bug-buddy launches while the screen is locked, and the only way to resume control is to log on from a text console and killall bug-buddy. If the stack trace is left somewhere, I don't know how to retrieve it. I'm not sure which is worse - that the screensaver crashes in the first place, or that it requires pretty esoteric knowledge to be able to recover from it without a reboot. Personally, I'd prefer it to just unlock my screen despite the obvious security issues that implies. This part is related to #562404 Other information: I'm using the Floating Fedora Bubbles screensaver, but based on the bug-buddy command line I see in ps output, I think it's gnome-screensaver's daemon that crashes..
I thought of disabling the password lock on screensaver as a way to collect the stack trace. However, that also stops the screensaver from crashing. I guess that should help locate the issue within the password dialog portion of gnome-screensaver.
Can you please try to log-in to the machine remotely and use the debug-screensaver.sh tool that is shipped with the gnome-screensaver sources to try to get a backtrace? You may need to modify the script to run gdb. Thanks a lot.
Created attachment 132646 [details] debug output as requested see attached log file. interestingly, the test case (in my original description) no longer crashes the process, but it doesn't allow me to unlock the display either (the password dialog is not visible).
I'm sorry -- the password dialog does still crash, but unlike before, the screensaver resumes (instead of just blanking the screen entirely). I still have to figure out how to catch the passphrase dialog subprocess in the gdb...
You can try just running the /usr/libexec/gnome-screensaver-dialog directly outside of the screensaver. You won't see any UI because it has nothing to embed into but it may help find your crash.
I no longer see this issue with gnome-screensaver-2.26.1-3.fc11.x86_64 (though it might be hidden by some stability issues with Xorg/intel multiscreen modesetting currently).