What WM/DE, what application?  Can it be easily reproduced?

KDE 3.5.8

In order to reproduce it, I just have to leave the PC idle for some half an hour.

The applications that usually stay on the foreground are Thunderbird, Gkrellm,
OpenOffice.org and Firefox.

What XOrg version and video driver?

Try to run xscreensaver with -verbose option and show log.

Created attachment 2250 [details]
xscreensaver -verbose

Created attachment 2251 [details]
Run with the -verbose option and waited until the bug reproduced itself.

Лёш, а мне сегодня с утра пришлось опять переключаться в консоль и килять
xscreensaver -- не отзывался.  В логе при этом было лишь:

Nov  3 13:02:43 pad xscreensaver: pam_tcb(xscreensaver:auth): conversation failed
Nov  3 13:02:43 pad xscreensaver: pam_tcb(xscreensaver:auth): Unable to obtain a
password

Недавно он в кнопку открывалки вместо "OK" писал "FAILED" чего-то там.  Передай
мужикам -- уже сломано, пора чинить ;-)

(In reply to comment #6)
> Nov  3 13:02:43 pad xscreensaver: pam_tcb(xscreensaver:auth): conversation failed

Вообще-то его надо было перезапустить после обновления до >= 5.02-alt1.  Там
поменялась работа с pam.  И проверить /etc/pam.d/ на тему .rpmnew, потому как
%config(noreplace).

xscreensaver: 02:46:09: blanking screen at Sat Nov  3 02:46:09 2007.
xscreensaver: 02:46:12: 0: grabbing keyboard on 0x58... AlreadyGrabbed.
xscreensaver: 02:46:13: couldn't grab keyboard!  (AlreadyGrabbed)
xscreensaver: 02:46:13: 0: removing focus from 0x280000b / RevertToPointerRoot.
xscreensaver: 02:46:17: 0: grabbing keyboard on 0x58... AlreadyGrabbed.
xscreensaver: 02:46:18: couldn't grab keyboard!  (AlreadyGrabbed)

Screen is not locked and window 0x280000b prevents keyboard and mouse to be grabbed.

Please repeat steps with xss -verbose, remember window id and attach:

xwininfo -root -tree
xwininfo -all -id ID_OF_PROBLEM_WINDOW

$ uptime
 17:47:11 up 1 day,  6:11,  1 user,  load average: 0.45, 0.11, 0.09
$ ls /etc/pam.d/*.rpm*
/bin/ls: /etc/pam.d/*.rpm*: No such file or directory

(In reply to comment #9)

sudo rpm -Vf /etc/pam.d/xscreensaver

И вообще, к этому багу оно отношения не имеет, а '"FAILED" чего-то там' означает
что xscreensaver не был перезапущен после обновления.

Created attachment 2299 [details]
xwininfo -root -tree

Created attachment 2300 [details]
xwininfo -all -id 0x360007f

Was it _locked_ again?  Is xscreensaver log lost?

I have no ideas.  Reported upstream...

From: Jamie Zawinski <jwz@jwz>

The answer is right there in the bug report -- some other app has the keyboard
grabbed.  I have no idea what that app is, or why, but it's impossible for
xscreensaver to lock the screen if it's unable to grab the keyboard.

Is flash plugin installed?  Is there any flash content somewhere in browser?

As far as I see, the conflict is that both KDE screensaver and xscreensaver are
activated. And the latter doesn't work properly under KDE.

Actually, it should be disabled, but as far as I can see it is invoked from
within somewhere around /etc/scriplets.d.

xscreensaver packages does not contain any autostart scripts nor XDG autostart
desktop files.  Two screensavers doesn't play well, but it's not xscreensaver's
problem.