Ubuntu
unity package

unity-panel-service crashed with SIGSEGV in atk_object_get_n_accessible_children()

Bug #863720 reported by Guy Schlosser on 2011-09-30

This bug report is a duplicate of: Bug #1040660: unity-panel-service crashed with SIGSEGV in panel_indicator_entry_accessible_get_n_children() from append_cache_item() from g_hash_table_foreach(). Edit Remove

186

This bug affects 42 people

Affects		Status	Importance	Assigned to	Milestone
	Unity	Confirmed	High	Unassigned
	unity (Ubuntu)	Confirmed	High	Unassigned

Bug Description

Log into Unity 2d with orca, and try navigating the launcher and dash. This bug is highly reproducible.

ProblemType: Crash
DistroRelease: Ubuntu 11.10
Package: unity-services 4.20.0-0ubuntu2
ProcVersionSignature: Ubuntu 3.0.0-12.19-generic-pae 3.0.4
Uname: Linux 3.0.0-12-generic-pae i686
NonfreeKernelModules: nvidia
.proc.driver.nvidia.gpus.0: Error: [Errno 21] Is a directory: '/proc/driver/nvidia/gpus/0'
.proc.driver.nvidia.registry: Binary: ""
.proc.driver.nvidia.version:
NVRM version: NVIDIA UNIX x86 Kernel Module 280.13 Wed Jul 27 16:55:43 PDT 2011
GCC version: gcc version 4.6.1 (Ubuntu/Linaro 4.6.1-9ubuntu3)
.tmp.unity.support.test.0:

ApportVersion: 1.23-0ubuntu2
Architecture: i386
CompizPlugins: [core,bailer,detection,composite,opengl,decor,grid,compiztoolbox,gnomecompat,regex,move,animation,vpswitch,resize,workarounds,imgpng,snap,mousepoll,place,wall,fade,unitymtgrabhandles,session,expo,ezoom,scale,unityshell]
CompositorRunning: None
Date: Fri Sep 30 18:41:59 2011
DistUpgraded: Log time: 2011-09-17 17:07:19.818068
DistroCodename: oneiric
DistroVariant: ubuntu
ExecutablePath: /usr/lib/unity/unity-panel-service
GraphicsCard:
nVidia Corporation G72 [GeForce 7300 LE] [10de:01d1] (rev a1) (prog-if 00 [VGA controller])
Subsystem: Dell Device [1028:0405]
InstallationMedia: Ubuntu 10.10 "Maverick Meerkat" - Beta i386 (20100901.1)
MachineType: Dell Inc. Dell DM061
ProcCmdline: /usr/lib/unity/unity-panel-service
ProcEnviron:
SHELL=/bin/bash
LANG=en_US.UTF-8
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.0.0-12-generic-pae root=UUID=5c17e2e5-c4ff-4c50-b45f-ad377fea3db7 ro quiet splash vt.handoff=7
SegvAnalysis:
Segfault happened at: 0x804c7c6: mov (%ebx),%edx
PC (0x0804c7c6) ok
source "(%ebx)" (0x00000038) not located in a known VMA region (needed readable region)!
destination "%edx" ok
SegvReason: reading NULL VMA
Signal: 11
SourcePackage: unity
StacktraceTop:
?? ()
atk_object_get_n_accessible_children () from /usr/lib/i386-linux-gnu/libatk-1.0.so.0
?? () from /usr/lib/gtk-3.0/modules/libatk-bridge.so
g_hash_table_foreach () from /lib/i386-linux-gnu/libglib-2.0.so.0
spi_cache_foreach () from /usr/lib/gtk-3.0/modules/libatk-bridge.so
Title: unity-panel-service crashed with SIGSEGV in atk_object_get_n_accessible_children()
UpgradeStatus: Upgraded to oneiric on 2011-09-17 (13 days ago)
UserGroups: adm admin cdrom dialout lpadmin plugdev sambashare vboxusers
XsessionErrors:
(nautilus:1895): Gtk-CRITICAL **: gtk_action_set_visible: assertion `GTK_IS_ACTION (action)' failed
(nautilus:1895): Gtk-CRITICAL **: gtk_action_set_visible: assertion `GTK_IS_ACTION (action)' failed
dmi.bios.date: 10/25/2006
dmi.bios.vendor: Dell Inc.
dmi.bios.version: 2.0.4
dmi.board.name: 0WG864
dmi.board.vendor: Dell Inc.
dmi.chassis.type: 6
dmi.chassis.vendor: Dell Inc.
dmi.modalias: dmi:bvnDellInc.:bvr2.0.4:bd10/25/2006:svnDellInc.:pnDellDM061:pvr:rvnDellInc.:rn0WG864:rvr:cvnDellInc.:ct6:cvr:
dmi.product.name: Dell DM061
dmi.sys.vendor: Dell Inc.
version.compiz: compiz 1:0.9.6+bzr20110929-0ubuntu1
version.libdrm2: libdrm2 2.4.26-1ubuntu1
version.libgl1-mesa-dri: libgl1-mesa-dri 7.11-0ubuntu3
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx 7.11-0ubuntu3
version.nvidia-graphics-drivers: nvidia-graphics-drivers N/A
version.xserver-xorg: xserver-xorg 1:7.6+7ubuntu7
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev 1:2.6.0-1ubuntu13
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:6.14.99~git20110811.g93fc084-0ubuntu1
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.15.901-1ubuntu2
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:0.0.16+git20110411+8378443-1

Tags:

Revision history for this message

Guy Schlosser (guyster104) wrote on 2011-09-30:

.proc.driver.nvidia.params.txt Edit (455 bytes, text/plain; charset="utf-8")
BootDmesg.txt Edit (59.2 KiB, text/plain; charset="utf-8")
BootLog.gz Edit (569 bytes, application/x-gzip)
CurrentDmesg.txt Edit (1.6 KiB, text/plain; charset="utf-8")
Dependencies.txt Edit (2.0 KiB, text/plain; charset="utf-8")
Disassembly.txt Edit (505 bytes, text/plain; charset="utf-8")
DkmsStatus.txt Edit (506 bytes, text/plain; charset="utf-8")
DpkgLog.txt Edit (2.4 MiB, text/plain; charset="utf-8")
GconfCompiz.txt Edit (37.1 KiB, text/plain; charset="utf-8")
GdmLog.txt Edit (33.1 KiB, text/plain; charset="utf-8")
GdmLog1.txt Edit (62.2 KiB, text/plain; charset="utf-8")
GdmLog2.txt Edit (11.5 KiB, text/plain; charset="utf-8")
JockeyStatus.txt Edit (627 bytes, text/plain; charset="utf-8")
LightdmDisplayLog.txt Edit (1.0 KiB, text/plain; charset="utf-8")
LightdmGreeterLog.txt Edit (19.6 KiB, text/plain; charset="utf-8")
LightdmLog.txt Edit (5.2 KiB, text/plain; charset="utf-8")
Lspci.txt Edit (9.8 KiB, text/plain; charset="utf-8")
Lsusb.txt Edit (1.0 KiB, text/plain; charset="utf-8")
ProcCpuinfo.txt Edit (1.5 KiB, text/plain; charset="utf-8")
ProcInterrupts.txt Edit (1.4 KiB, text/plain; charset="utf-8")
ProcMaps.txt Edit (29.2 KiB, text/plain; charset="utf-8")
ProcModules.txt Edit (2.0 KiB, text/plain; charset="utf-8")
ProcStatus.txt Edit (789 bytes, text/plain; charset="utf-8")
Registers.txt Edit (465 bytes, text/plain; charset="utf-8")
Stacktrace.txt Edit (1.5 KiB, text/plain; charset="utf-8")
ThreadStacktrace.txt Edit (3.5 KiB, text/plain; charset="utf-8")
UdevDb.txt Edit (124.0 KiB, text/plain; charset="utf-8")
UdevLog.txt Edit (247.5 KiB, text/plain; charset="utf-8")
UnitySupportTest.txt Edit (588 bytes, text/plain; charset="utf-8")
XorgConf.txt Edit (274 bytes, text/plain; charset="utf-8")
XorgLog.txt Edit (19.6 KiB, text/plain; charset="utf-8")
XorgLogOld.txt Edit (19.4 KiB, text/plain; charset="utf-8")
Xrandr.txt Edit (9.0 KiB, text/plain; charset="utf-8")
dmidecode.txt.txt Edit (15.6 KiB, text/plain; charset="utf-8")
locale.txt Edit (327 bytes, text/plain; charset="utf-8")
nvidia-settings.txt Edit (73.0 KiB, text/plain; charset="utf-8")
peripherals.txt Edit (731 bytes, text/plain; charset="utf-8")
setxkbmap.txt Edit (233 bytes, text/plain; charset="utf-8")
xdpyinfo.txt Edit (30.6 KiB, text/plain; charset="utf-8")
xinput.txt Edit (680 bytes, text/plain; charset="utf-8")
xkbcomp.txt Edit (54.1 KiB, text/plain; charset="utf-8")

Revision history for this message

Apport retracing service (apport) wrote on 2011-10-03:

StacktraceTop:
panel_indicator_entry_accessible_get_n_children (accessible=0x965b1b0) at /build/buildd/unity-4.20.0/services/panel-indicator-entry-accessible.c:256
atk_object_get_n_accessible_children (accessible=0x965b1b0) at atkobject.c:800
append_cache_item (obj=0x965b1b0, data=0xbff71a98) at cache-adaptor.c:153
g_hash_table_foreach (hash_table=0x96ac318, func=0xb64dd770 <append_accessible_hf>, user_data=0xbff71a98) at /build/buildd/glib2.0-2.30.0/./glib/ghash.c:1420
spi_cache_foreach (cache=0xb5b14b80, func=0xb64dd770 <append_accessible_hf>, data=0xbff71a98) at ../../atk-adaptor/accessible-cache.c:417

Revision history for this message

Apport retracing service (apport) wrote on 2011-10-03: Stacktrace.txt

Stacktrace.txt Edit (5.6 KiB, text/plain)

Revision history for this message

Apport retracing service (apport) wrote on 2011-10-03: ThreadStacktrace.txt

ThreadStacktrace.txt Edit (10.0 KiB, text/plain)

Changed in unity (Ubuntu):
importance:	Undecided → Medium
tags:	removed: need-i386-retrace

Didier Roche-Tolomelli (didrocks) on 2011-10-25

Changed in unity (Ubuntu):
importance:	Medium → Critical

Revision history for this message

Launchpad Janitor (janitor) wrote on 2011-11-09:

Status changed to 'Confirmed' because the bug affects multiple users.

Changed in unity (Ubuntu):
status:	New → Confirmed

Michal Hruby (mhr3) on 2011-11-09

tags:

added: a11y

Michal Hruby (mhr3) on 2011-11-10

visibility:

private → public

Revision history for this message

Alejandro Piñeiro (apinheiro) wrote on 2011-11-10:

I had a interesting talking with mhr3 about this bug. It crashes in this line:

if (GTK_IS_MENU (piea->priv->entry->menu))

So probably entry is NULL, or menu is not anymore a valid object.

Taking a look to the code, this is a custom atk object associated to a non-GTK object. Taking a look to the parent (ParentIndicatorAccessible) it have a callback when the entry is removed, so it is removed from the list. But PanelIndicatorEntryAccessible doesn't have any code managing this.

As the accessibility object can survive the base object, atk objects requires to manage if the base object is destroyed, and changing his state to ATK_STATE_DEFUNCT accordingly. So the atk-bridge will usually not interact with a accessible object with that state.

In the case of gtk, they implement this adding a weak_ref to the base object. But as I said this is custom atk object (not a gtkaccessible subclass). As far as I see the purpose of this object is expose the menu.

So I think that it is worth to add a weak_ref to entry->menu. If the crash happens because the entry->menu is freed, then ATK_STATE_DEFUNCT management should be added. The easiest way to do that:

  * add that weak_ref to the menu: when the menu is destroyed notify the state change and save somehow that the object was destroyed
       atk_object_notify_state_change (self, ATK_STATE_DEFUNCT)
  * return ATK_STATE_DEFUNCT on panel_indicator_entry_accessible_ref_state_set if the menu was destroyed

BTW: in order to return the ROLE and NAME on the initialize method, it is check entry->label and entry->image, instead of entry->menu. Not sure if this is correct. Probably it is worth to ask Rodrigo Moya about it.

Didier Roche-Tolomelli (didrocks) on 2011-11-22

Changed in unity:
status:	New → Confirmed

Revision history for this message

SamHu (hsy19891228) wrote on 2012-02-22:

I got same when i am using 3d unity, i guess it has something to do with gui lib like qt because it always happen when i am using qucs or other qt app

Revision history for this message

emptythevoid (emptythevoid) wrote on 2012-05-17:

Just happened to me with Unity 3D. Had Totem open, and the panel vanished and returned quickly.

Revision history for this message

Marco Biscaro (marcobiscaro2112) wrote on 2012-05-22:

This same error occurs in precise, when using Eclipse and changing tabs (see duplicate bug #997444).

tags:

added: precise
removed: i386

Revision history for this message

Karthik Inbasekar (karthik-inbasekar) wrote on 2012-06-20:

#10

Verified that the Bug #997444 referenced above happens when using Kile Latex editor and changing tabs.
using Ubuntu 12.04 precise.

Revision history for this message

Antec (info-janmob) wrote on 2012-06-29:

#11

Crashes for me with 12.04 and kernel 3.5.0-2-generic

Revision history for this message

Antec (info-janmob) wrote on 2012-06-29:

#12

Sorry I mean of course that it crashes for me with 12.10 and kernel 3.5.0-2-generic.

Omer Akram (om26er) on 2012-07-24

Changed in unity:
importance:	Undecided → High
Changed in unity (Ubuntu):
status:	Confirmed → Incomplete
importance:	Critical → High
Changed in unity:
status:	Confirmed → Incomplete
status:	Incomplete → Confirmed
Changed in unity (Ubuntu):
status:	Incomplete → Confirmed

Revision history for this message

Leodardo (leodardo) wrote on 2012-10-31:

#13

I have this bug happening continuosly with Kile (see bug #997444).
I have this with Ubuntu 12.04 i386, Unity-2d and Unity-3d (unity -v: 5.16.0) and previous, kernel 3.2.0-32-generic-pae and previous.
The panel takes several seconds to die and restart making Kile unusable during this period and the system very slow.
Being an academic I work with latex a lot and this is very frustrating with this bug.

As it seems to persist still with 12.10, the bug needs be assigned to a developer.

Revision history for this message

DFOXpro (dfoxpro) wrote on 2013-07-24:

#14

I just use unity 2d panel (12.04) and no orca, btw it still crash

Revision history for this message

Floris Van den Abeele (florisvda) wrote on 2013-08-14:

#15

I can confirm comment #13, when working with Kile the unity-panel-service crashes everytime a tab is switched in Kile (i.e. this triggers the titel in the panel to be updated I suppose). I've tried running unity in verbose and debug mode, but the unity-panel-service process crashing doesn't get captured when running `unity --verbose --debug'.

Revision history for this message

Floris Van den Abeele (florisvda) wrote on 2013-08-14:

#16

_usr_lib_unity_unity-panel-service.1000.crash Edit (13.8 MiB, text/plain)

So far I can only provide the crash file attached, note that I'm running plain unity (not 2d as the OP). Running unity 5.20.0 by the way.

Revision history for this message

Stephen M. Webb (bregma) wrote on 2013-08-14:

#17

Thank you for trying to make Ubuntu better. The stack trace in the attached .crash file in comment #16 shows a completely different problem than the one reported in this bug. Please open a new bug by using the "ubuntu-bug _usr_lib_unity_unity-panel-service.1000.crash" command from the terminal and include your nicely detailed description of how we can reproduce the problem so we can handle it appropriately.

Revision history for this message

Floris Van den Abeele (florisvda) wrote on 2013-08-19:

#18

I've created a new report at https://bugs.launchpad.net/ubuntu/+source/unity/+bug/1213829. Apologies for polluting this report though.

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unity-panel-service crashed with SIGSEGV in atk_object_get_n_accessible_children()

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