Bug#481191: gnome-settings-daemon under vnc segfaults

[John Gruenenfelder]

On Mon, Nov 10, 2008 at 02:23:22PM +0100, Josselin Mouette wrote:
>Le lundi 10 novembre 2008 à 01:35 -0700, John Gruenenfelder a écrit :
>> This bug still exists in the current gnome-settings-daemon package in
>> Debian/testing on an x86_64 system.  It occurs with both vnc4server and
>> tightvncserver.  In addition to not starting for the reason in the previous
>> message, it also segfaults on my system.  From dmesg output:
>> 
>> [192800.411880] gnome-settings-[19205]: segfault at 10 ip 7fe9ab245a1d sp 7fffb4c214a0 error 4 in libmouse.so[7fe9ab240000+a000]
>> [192802.415670] gnome-settings-[19216]: segfault at 10 ip 7fd87a780a1d sp 7fff8415b9b0 error 4 in libmouse.so[7fd87a77b000+a000]
>> [192802.683229] gnome-settings-[19229]: segfault at 10 ip 7f84816b2a1d sp 7fff8b08ffa0 error 4 in libmouse.so[7f84816ad000+a000]
>> [192803.100619] gnome-settings-[19242]: segfault at 10 ip 7f830adb9a1d sp 7fff14794fe0 error 4 in libmouse.so[7f830adb4000+a000]
>
>This looks like a different, though related bug. Could you please
>provide a backtrace? See http://wiki.debian.org/HowToGetABacktrace

Okay, I built the gnome-settings-daemon debug package and installed it.
Unfortunately, the system now behaves differently than it did before.

At first, I tried running gnome-settings-daemon from a terminal window in my
already active VNC session.  This did *not* result in a segfault.  Instead I
got an X error and no segfault.  I forgot to mention this last time, but this
error was present in the VNC log using the regular gnome-settings-daemon
package.  Here is the relevant text from the VNC/X log:

----------
** (gnome-settings-daemon:25963): WARNING **: numlock: XkbQueryExtension
returned an error

** (gnome-settings-daemon:25963): WARNING **: Neither XKeyboard not Xfree86's
keyboard extensions are available, no way to support keyboard autorepeat rate
settings
Xlib:  extension "XInputExtension" missing on display ":42.0".
Xlib:  extension "XInputExtension" missing on display ":42.0".
Xlib:  extension "XInputExtension" missing on display ":42.0".
Xlib:  extension "XInputExtension" missing on display ":42.0".

** (gnome-settings-daemon:25963): WARNING **: Unable to start a11y_keyboard
manager: XKB functionality is disabled.

** (gnome-settings-daemon:25963): WARNING **: Unable to start screensaver
manager: No screensaver available.
<stdin>:130:14: warning: missing terminating ' character
Window manager warning: Log level 32: could not find XKB extension.
Initializing gnome-mount extension
The program 'gnome-settings-daemon' received an X Window System error.
This probably reflects a bug in the program.
The error was 'BadWindow (invalid Window parameter)'.
  (Details: serial 2360 error_code 3 request_code 20 minor_code 0)
  (Note to programmers: normally, X errors are reported asynchronously;
   that is, you will receive the error a while after causing it.
   To debug your program, run it with the --sync command line
   option to change this behavior. You can then get a meaningful
   backtrace from your debugger if you break on the gdk_x_error() function.)
----------

Now, that's the same as before.  If I run g-s-d from the command line I get
similar output in the terminal window and no crash.  I did try running g-s-d
--sync from within gdb trying to break on gdk_x_error, but it did not break.
It ran to conclusion with an exit code of 1.

So I killed the VNC session and started a new one, figuring that Gnome was
starting g-s-d with parameters I was not passing.

Previously, g-s-d would segfault four times and then Gnome would give up.
Now, it segfaults once and then actually starts.  Also, I get the following
error dialog text from Nautilus:

"Nautilus can't be used now, due to an unexpected error from Bonobo when
attempting to locate the factory. Killing bonobo-activation-server and
restarting Nautilus may help fix the problem."

And then Nautilus proceeds to start normally.  So, at this point I now have a
working desktop under VNC with the only oddity being some unusual log messages
and one error dialog.

Even though it is usable now, it still segfaults once at startup.  What can I
do now to debug this further?


-- 
--John Gruenenfelder    Systems Manager, MKS Imaging Technology, LLC.
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