Bug#294182: system lockup whenever "molecule" runs (even in screensaver preview window)
> On Tue, 2005-19-04 at 10:14 -0700, John Gilmore wrote:
> > When the X server hangs, there's no way to affect it from the console.
> > Ctrl-alt-backspace doesn't work. Nothing moves on the display. However,
> > I can login to the machine over the net. When I do, the system is
> > idle (the X server isn't burning CPU). I see an xscreensaver process
> > but don't see any screensaver running.
>
> So the molecule process is no longer there? What happens if you kill
> xscreensaver or the X server?
This time it was the starwars process -- not molecule -- that caused the
hang. I had turned off molecule (as described in earlier entries in this
bug).
Yes, the process appears not to be there. I couldn't find any process that
looked like the screen saver, and xscreensaver has no child processes.
Now it's a day later than my message quoted above -- now there's no
xscreensaver process either, so I can't kill it.
X is process 1691. When I do "kill 1691", nothing happens. The screen
remains the same (to paraphrase led zeppelin). The process is still there
too.
When I do "kill -9 1691", the screen remains the same for about five
to ten seconds; then goes black; then about ten seconds later I get
a grey stipple background with a circular cursor, rotating; then the GDM
display comes up and asks me to log in. The machine appears to be OK
after that.
> > This bug has been reported two years ago, one year ago, and seventy
> > days ago (by different people).
>
> Which other bugs are you talking about? FWIW, this bug is probably in
> r128_dri.so, so it should be reassigned to xlibmesa-dri.
They're not hard to find -- they're three of the top five outstanding
bugs against this package.
http://bugs.debian.org/cgi-bin/pkgreport.cgi?pkg=xlibmesa-gl
Important bugs - outstanding (5 bugs)
* #179660: xlibmesa-gl: bzflag freezes the X server seemingly randomly
Package: xlibmesa-gl; Severity: important; Reported by: Remco Seesink <raseesink@hotpop.com>; Tags: moreinfo, upstream; 2 years and 75 days old.
* #227553: xlibmesa-gl: system locks up while playing foobilliard on Matrox MGA G200
Package: xlibmesa-gl; Severity: important; Reported by: willy <linuxxirro@yahoo.it>; Tags: moreinfo, upstream; 1 year and 96 days old.
* #294182: xlibmesa-gl: system lockup whenever "molecule" runs (even in screensaver preview window)
Package: xlibmesa-gl; Severity: important; Reported by: John Gilmore <gnu@debianbug.toad.com>; 70 days old.
> > I can reproduce it easily on a machine that I'm happy to give a developer
> > access to. It makes the entire machine unusable without a reboot (or
> > intervention from across the network), from the screen saver. Can
> > someone spare a few hours to debug it?
>
> Heh. This isn't the kind of problem that's usually fixed in a few hours.
My offer stands. I see little chance that someone will debug it
WITHOUT access to a machine where it fails.
I could just turn off all the OpenGL-based screen savers on my
machine, but what would be the point of that? We're trying to make a
stable and reliable Debian sarge release, and this turns itself on
when the machine is idle, then hangs the system so you have to hit
RESET (unless you have a network connection you can log in on). It
would be kinda dumb to just ignore a show-stopper like this.
> I think you mean 'starwars'.
Yes, this is the "starwars" screen saver.
I tried running both these screensavers in demo mode today, for five
or ten minutes each, and neither one hung the system. Seems to be less
reproducible than I'd thought.
John
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