unity-greeter crashed with SIGSEGV in indicator_object_get_entries()

[Daniel Hahler]

Since the last updates, I cannot log in through lightdm anymore: it appears the unity greeter is crashing, before I see the password dialog/prompt.

I can login using "startx" and when using "gdm" as default display manager.

ProblemType: Crash
DistroRelease: Ubuntu 12.04
Package: unity-greeter 0.2.0-0ubuntu5
ProcVersionSignature: Ubuntu 3.2.0-10.18-generic-pae 3.2.1
Uname: Linux 3.2.0-10-generic-pae i686
ApportVersion: 1.91-0ubuntu1
Architecture: i386
Date: Thu Jan 26 10:40:39 2012
ExecutablePath: /usr/sbin/unity-greeter
InstallationMedia: Ubuntu 11.04 "Natty Narwhal" - Release i386 (20110427.1)
ProcCmdline: /usr/sbin/unity-greeter
ProcEnviron:
 LC_TIME=en_US.UTF-8
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 SHELL=/bin/false
SegvAnalysis:
 Segfault happened at: 0xb77b2090 <indicator_object_get_entries+64>: mov 0xc(%eax),%eax
 PC (0xb77b2090) ok
 source "0xc(%eax)" (0x0000000c) not located in a known VMA region (needed readable region)!
 destination "%eax" ok
SegvReason: reading NULL VMA
Signal: 11
SourcePackage: unity-greeter
StacktraceTop:
 indicator_object_get_entries () from /usr/lib/libindicator3.so.7
 ?? ()
 g_object_newv () from /usr/lib/i386-linux-gnu/libgobject-2.0.so.0
 g_object_new_valist () from /usr/lib/i386-linux-gnu/libgobject-2.0.so.0
 g_object_new () from /usr/lib/i386-linux-gnu/libgobject-2.0.so.0
Title: unity-greeter crashed with SIGSEGV in indicator_object_get_entries()
UpgradeStatus: Upgraded to precise on 2011-12-16 (41 days ago)
UserGroups:

[Apport retracing service (apport)]

StacktraceTop:
 indicator_object_get_entries (io=0x0) at /build/buildd/libindicator-0.4.90/./libindicator/indicator-object.c:605
 menu_bar_setup_indicators (self=0x8401038) at menubar.c:785
 menu_bar_constructor (type=138386632, n_construct_properties=1, construct_properties=0x83f72e0) at menubar.c:1404
 g_object_newv (object_type=138386632, n_parameters=1, parameters=0x83f7148) at /build/buildd/glib2.0-2.31.12/./gobject/gobject.c:1703
 g_object_new_valist (object_type=138386632, first_property_name=0x805c934 "background", var_args=0xbfe7f010 "40.\267\b") at /build/buildd/glib2.0-2.31.12/./gobject/gobject.c:1820

[Launchpad Janitor (janitor)]

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

[Sebastien Bacher (seb128)]

The greeter segfaults if indicator-datetime is not installed, Michael could you look at it? One easy workaround is to add a Depends but ideally the greeter wouldn't segfault

[Sebastien Bacher (seb128)]

In fact there is a patch waiting for review on https://code.launchpad.net/~jconti/ubuntu/precise/unity-greeter/fix_921953/+merge/90320

[Sebastien Bacher (seb128)]

comment from bug #921953

"Can everyone experiencing this issue please check the greeter log in /var/log/lightdm/ and look for a line similar to:

WARNING: File '/usr/lib/indicators3/7/libdatetime.so' does not exist

and if you find it, make sure indicator-datetime is installed. The issue, based on a discussion in irc, seems to be that unity-greeter doesn't check for a null indicator object after attempting to load it from a file in src/menubar.vala:304."

[Fabien Tassin (fta)]

crashes for me but indicator-datetime is installed... but /usr/lib/indicators3/7/libpower.so is not.

[+0.08s] DEBUG: menubar.vala:450: Adding indicator object 0x25e42d8 at position 1
[+0.08s] WARNING: File '/usr/lib/indicators3/7/libpower.so' does not exist.
[+0.08s] WARNING: invalid (NULL) pointer instance
[+0.08s] CRITICAL: g_signal_connect_object: assertion `G_TYPE_CHECK_INSTANCE (instance)' failed
[+0.08s] WARNING: invalid (NULL) pointer instance
[+0.08s] CRITICAL: g_signal_connect_object: assertion `G_TYPE_CHECK_INSTANCE (instance)' failed
[+0.08s] CRITICAL: get_all_entries: assertion `INDICATOR_IS_OBJECT(io)' failed

[LaMont Jones (lamont)]

Somewhere in the pile, there is a missing Depends: indicator-datetime indicator-power. Installing both of those packages lets the unity-greeter run again.

The failure mode of X constantly launching something that dies does make debugging it rather painful. It would be good to wrap unity-greeter with something that counts how many times it dies, and if it gets high enough, STOPS LAUNCHING IT and does a sleep 9999999h. That way, one can switch to another vt to deal with it, instead of needing to reboot, break, and chmod a-x /usr/bin/X or so to get it to stop hurting so much.

[Ritesh Raj Sarraf (rrs)]

On 01/28/2012 04:24 AM, LaMont Jones wrote:
> Somewhere in the pile, there is a missing Depends: indicator-datetime
> indicator-power. Installing both of those packages lets the unity-
> greeter run again.
>
> The failure mode of X constantly launching something that dies does make
> debugging it rather painful. It would be good to wrap unity-greeter
> with something that counts how many times it dies, and if it gets high
> enough, STOPS LAUNCHING IT and does a sleep 9999999h. That way, one can
> switch to another vt to deal with it, instead of needing to reboot,
> break, and chmod a-x /usr/bin/X or so to get it to stop hurting so much.

Totally agree. The way the failure occured, it tooks my a couple reboots
to narrow it down to libghtdm. Even saKing the process didn't help. It
froze the system.

Ritesh

--
Ritesh Raj Sarraf
RESEARCHUT - http://www.researchut.com
"Necessity is the mother of invention."

[Sebastien Bacher (seb128)]

Jason, thanks for your work, do you think you could do an upstream merge request against lp:unity-greeter?

[Robert Ancell (robert-ancell)]

Jason's patch is committed to trunk which should allow unity-greeter to gracefully handle missing indicators. The packaging branch has also been updated to recommend the default indicators.

[Launchpad Janitor (janitor)]

This bug was fixed in the package unity-greeter - 0.2.0-0ubuntu6

---------------
unity-greeter (0.2.0-0ubuntu6) precise; urgency=low

  * debian/patches/handle_missing_indicators.patch:
    - backported from trunk, handle missing indicators (lp: #921998)
  * debian/patches/working_session_selector.patch:
    - backported from trunk, make the session selector work (lp: #918657)

  [ Robert Ancell ]
  * debian/control:
    - Add recommends on indicator-session, indicator-datetime, indicator-power,
      indicator-sound (LP: #921998)
 -- Sebastien Bacher <email address hidden> Tue, 31 Jan 2012 18:59:57 +0100