Lightdm can get stuck in an endless loop, makes system unusable

[Daniel]

Hello,

it is possible for lightdm to get stuck in an endless loop.
For example, on my system the nouveau driver doesn't resume correctly from standby, which causes the X server to die. Lightdm will then try to start X again, to show the login screen. However, the X server will crash again (because of nouveau), and lightdm will again try to start X, which dies again, ad nauseam.
Please note that nouveau is just being used as an example I can confirm. There are conceivably many reasons for the X server to crash repeatedly; lightdm should be prepared to handle this, for example by refusing to run again after a certain number of restarts in a given time interval have happend.
The current behaviour is very bad, as the constant "start and crash" cycle of X11 makes it almost impossible to log in on the console to
# stop lightdm

Regards,
Daniel

ProblemType: Bug
DistroRelease: Ubuntu 12.10
Package: lightdm 1.4.0-0ubuntu2
Uname: Linux 3.7.1-030701-generic x86_64
ApportVersion: 2.6.1-0ubuntu9
Architecture: amd64
CheckboxSubmission: 9ba752561746ae67a26232661222f63a
CheckboxSystem: b1865df84255b8716d3bcc269ff410d1
Date: Mon Jan 7 03:15:42 2013
InstallationDate: Installed on 2011-10-25 (439 days ago)
InstallationMedia: Ubuntu 11.10 "Oneiric Ocelot" - Release amd64 (20111012)
MarkForUpload: True
SourcePackage: lightdm
UpgradeStatus: Upgraded to quantal on 2012-12-25 (12 days ago)