Variables defined twice in config files lead to crash

You've probably chose to keep your current configuration file (/etc/lightdm/lightdm.conf) on LightDM upgrade.
If it's so, comment/erase these lines there:

greeter-session=lightdm-greeter
session-wrapper=/etc/X11/Xsession

Those lines do not exist. I purged and reinstalled LightDM and the same
error occurred.

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Roland L. Taylor
about.me/rolandixor
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On Wed, Oct 8, 2014 at 3:24 AM, Monsta <email address hidden> wrote:

> You've probably chose to keep your current configuration file
> (/etc/lightdm/lightdm.conf) on LightDM upgrade.
> If it's so, comment/erase these lines there:
>
> greeter-session=lightdm-greeter
> session-wrapper=/etc/X11/Xsession
>
> --
> You received this bug notification because you are subscribed to the bug
> report.
> https://bugs.launchpad.net/bugs/1377373
>
> Title:
> Lightdm crashes on startup
>
> Status in Light Display Manager:
> New
> Status in “lightdm” package in Debian:
> Incomplete
>
> Bug description:
> Lightdm crashes on startup for me, on Ubuntu 14.10.
>
> This is the offending error:
>
> *** Error in `lightdm': double free or corruption (fasttop):
> 0x0000000002535ca0 ***
> Aborted
>
> To manage notifications about this bug go to:
> https://bugs.launchpad.net/lightdm/+bug/1377373/+subscriptions
>

Note that this is a regression.

Ok, this seem to have fixed the double or free corruption issue, however, lightdm still doesn't start for me:

[+0.26s] DEBUG: Session pid=1890: Greeter connected version=1.10.2
[+0.53s] DEBUG: Session pid=1890: Greeter closed communication channel
[+0.53s] DEBUG: Session pid=1890: Exited with return value 6
[+0.53s] DEBUG: Seat: Session stopped
[+0.53s] DEBUG: Seat: Stopping; failed to start a greeter
[+0.53s] DEBUG: Seat: Stopping
[+0.53s] DEBUG: Seat: Stopping display server

Seems like lightdm-gtk-greeter needs to be updated as well.

Adrian

Addendum:

From /var/log/lightdm/x-0-greeter.log:

*** Error in `/usr/sbin/lightdm-gtk-greeter': double free or corruption (fasttop): 0x00007f22865207c0 ***

This bug was fixed in the package lightdm - 1.12.1-0ubuntu1

---------------
lightdm (1.12.1-0ubuntu1) utopic; urgency=medium

  * New upstream release:
    - Fix crash when having configuration keys defined in multiple places
      (LP: #1377373)
    - Allow user switching in multi-seat until bug stopping greeter showing on
      logout is fixed
    - Disable log message when AccountsService users change (LP: #1376357)
 -- Robert Ancell <email address hidden> Thu, 09 Oct 2014 08:59:27 +1300

John - we you running the updated liblightdm? Both the daemon and this library use the same code and so should both be fixed on update.

Hello Roland, or anyone else affected,

Accepted lighdm into trusty-proposed. The package will build now and be available at http://launchpad.net/ubuntu/+source/lighdm/1.10.3-0ubuntu2 in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested, and change the tag from verification-needed to verification-done. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed. In either case, details of your testing will help us make a better decision.

Further information regarding the verification process can be found at https://wiki.ubuntu.com/QATeam/PerformingSRUVerification . Thank you in advance!

Confirmed fixed in 1.10.3-0ubuntu2

This bug was fixed in the package lightdm - 1.10.3-0ubuntu2

---------------
lightdm (1.10.3-0ubuntu2) trusty; urgency=medium

  * Refresh patches
 -- Robert Ancell <email address hidden> Fri, 10 Oct 2014 21:24:51 +1300