gnome-screensaver crashed with SIGSEGV in gs_manager_set_active()

[Kayvan Sylvan]

Binary package hint: gnome-screensaver

I clicked on the Power-button->"Lock screen" choice and was able to reproduce the crash each time.

This host is a KVM guest.

kayvan@ksub10beta:~$ uname -a
Linux ksub10beta 2.6.32-19-generic #28-Ubuntu SMP Thu Apr 1 10:39:41 UTC 2010 x86_64 GNU/Linux

kayvan@ksub10beta:~$ lsb_release -rd
Description: Ubuntu lucid (development branch)
Release: 10.04
kayvan@ksub10beta:~$

kayvan@ksub10beta:~$ apt-cache policy gnome-screensaver
gnome-screensaver:
  Installed: 2.30.0-0ubuntu1
  Candidate: 2.30.0-0ubuntu1
  Version table:
 *** 2.30.0-0ubuntu1 0
        500 http://us.archive.ubuntu.com/ubuntu/ lucid/main Packages
        100 /var/lib/dpkg/status

ProblemType: Crash
DistroRelease: Ubuntu 10.04
Package: gnome-screensaver 2.30.0-0ubuntu1
ProcVersionSignature: Ubuntu 2.6.32-19.28-generic 2.6.32.10+drm33.1
Uname: Linux 2.6.32-19-generic x86_64
Architecture: amd64
Date: Thu Apr 8 13:49:16 2010
Disassembly: => 0x0: Cannot access memory at address 0x0
ExecutablePath: /usr/bin/gnome-screensaver
GnomeSessionIdleInhibited: No
GnomeSessionInhibitors: None
InstallationMedia: Ubuntu 10.04 "Lucid Lynx" - Beta amd64 (20100318)
ProcCmdline: gnome-screensaver
ProcEnviron:
 PATH=(custom, user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SegvAnalysis:
 Segfault happened at: 0x0: Cannot access memory at address 0x0
 PC (0x00000000) not located in a known VMA region (needed executable region)!
SegvReason: executing NULL VMA
Signal: 11
SourcePackage: gnome-screensaver
StacktraceTop:
 ?? ()
 ?? ()
 gs_manager_set_active ()
 ?? ()
 gs_marshal_BOOLEAN__BOOLEAN ()
Title: gnome-screensaver crashed with SIGSEGV in gs_manager_set_active()
UserGroups: adm admin cdrom dialout lpadmin plugdev sambashare
WindowManager: gnome-wm

[Apport retracing service (apport)]

StacktraceTop:
 ?? ()
 gs_fade_start (fade=0x224f400, timeout=1000)
 gs_manager_set_active (manager=0x220ba80,
 listener_active_changed_cb (
 gs_marshal_BOOLEAN__BOOLEAN (closure=0x2260bc0,

[Jens Maus (jens.maus)]

I also get the same kind of crashes of gnome-screenaver daemon as soon as "gnome-screensaver-command -a" is used. Please note, however, that this happens with a remote X connection to a Sunray. But the stacktrace looks quite similar. I Have started "/usr/bin/gnome-screenaver" with the option "--no-daemon" and then when issuing the "/usr/bin/gnome-screensaver-command -a" command to activate the screensaver the daemon immediately exists with a Segfault. Here is the stacktrace:

-- cut here --
Starting program: /usr/bin/gnome-screensaver --no-daemon
[Thread debugging using libthread_db enabled]

Program received signal SIGSEGV, Segmentation fault.
0x0000000000000000 in ?? ()
(gdb) bt
#0 0x0000000000000000 in ?? ()
#1 0x000000000041c6e9 in ?? ()
#2 0x0000000000411ed9 in gs_manager_set_active ()
#3 0x000000000040c028 in ?? ()
#4 0x000000000041d712 in gs_marshal_BOOLEAN__BOOLEAN ()
#5 0x00007ffff4c9b5de in g_closure_invoke () from /usr/lib/libgobject-2.0.so.0
#6 0x00007ffff4caf598 in ?? () from /usr/lib/libgobject-2.0.so.0
#7 0x00007ffff4cb08b9 in g_signal_emit_valist () from /usr/lib/libgobject-2.0.so.0
#8 0x00007ffff4cb1033 in g_signal_emit () from /usr/lib/libgobject-2.0.so.0
#9 0x000000000040e702 in gs_listener_set_active ()
#10 0x000000000040f9ea in ?? ()
#11 0x000000000040ff3c in ?? ()
#12 0x0000000000410482 in ?? ()
#13 0x00007ffff798c3a6 in dbus_connection_dispatch () from /lib/libdbus-1.so.3
#14 0x00007ffff7bc4e45 in ?? () from /usr/lib/libdbus-glib-1.so.2
#15 0x00007ffff41c88c2 in g_main_context_dispatch () from /lib/libglib-2.0.so.0
#16 0x00007ffff41cc748 in ?? () from /lib/libglib-2.0.so.0
#17 0x00007ffff41ccc55 in g_main_loop_run () from /lib/libglib-2.0.so.0
#18 0x00007ffff6e11af7 in gtk_main () from /usr/lib/libgtk-x11-2.0.so.0
#19 0x000000000040b893 in main ()
-- cut here --

dmesg also outputs the following segfault information:

-- cut here --
gnome-screensav[13614]: segfault at 0 ip (null) sp 00007fffb654b4c8 error 14 in gnome-screensaver[400000+27000]
-- cut here --

Here some information on the system:

Description: Ubuntu 10.04 LTS
Release: 10.04

gnome-screensaver:
  Installed: 2.30.0-0ubuntu1
  Candidate: 2.30.0-0ubuntu1
  Version table:
 *** 2.30.0-0ubuntu1 0
        500 http://de.archive.ubuntu.com/ubuntu/ lucid/main Packages
        100 /var/lib/dpkg/status

Linux titan 2.6.32-21-server #32-Ubuntu SMP Fri Apr 16 09:17:34 UTC 2010 x86_64 GNU/Linux

[Chris Coulson (chrisccoulson)]

Thank you for your bug report. Could you please run "killall gnome-screensaver && gnome-screensaver --no-daemon --debug 2>&1 | tee ~/gnome-screensaver.log", recreate the crash and then attach the log file here. I have a suspicion about what is happening here, but the log file will confirm it for me.

Thanks

[Jens Maus (jens.maus)]

Thanks for you fast reply. Please find attached the cathed debug log when gnome-screensaver crashes when issuing a "gnome-screensaver-command -a". Would be great to get that fixed ASAP as this seems to be the only issue that is currently holding back us from deploying ubuntu 10.04 to our main servers. ;)

[Chris Coulson (chrisccoulson)]

[gs_fade_init] gs-fade.c:906 (13:32:47): Fade type: 0

Ok, I think I see what happens here then

Thanks

[Jens Maus (jens.maus)]

Ok. let me know if you have some intermediate debug version I could test and see if the issue is fixed. Would love to test that here.
Thanks

[Colin Watson (cjwatson)]

Accepted gnome-screensaver into lucid-proposed, the package will build now and be available in a few hours. Please test and give feedback here. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you in advance!

[Filip Palm (filip)]

Colin,
This fix works like a charm.

Thanks.

[Jens Maus (jens.maus)]

Here the same. The fix works as expected.
regards

[Launchpad Janitor (janitor)]

This bug was fixed in the package gnome-screensaver - 2.30.0-0ubuntu2

---------------
gnome-screensaver (2.30.0-0ubuntu2) lucid-proposed; urgency=low

  * debian/patches/15_dont_crash_on_no_fade.patch:
    - Don't crash on systems that don't support XF86VM or XRANDR gamma fade,
      by testing if fade is supported on a particular screen before
      calling the fade_setup and fade_finish virtual functions (LP: #558721)
  * debian/patches/16_dont_crash_in_kvm.patch:
    - Don't crash when the XF86VM extension doesn't allow the gamma
      to be set (LP: #581864)
  * debian/patches/14_no_fade_on_user_switch.patch:
    - Disable fade on locking to work around LP: #546578 and prevent
      the screen remaining blank after user switching. The screensaver
      will still fade-in on idle though
 -- Chris Coulson <email address hidden> Wed, 19 May 2010 11:51:40 +0100

[Martin Pitt (pitti)]

Copied to maverick, too.