unity-greeter crashed with SIGSEGV in start_thread() - appears to go into a loop restarting itself. not allowing me time to type the password or change the user account.

[Axiano Ltd.]

What happened when the problem first appeared:
- I was logged on with one account and wanted to switch to another. When selecting the second user account the password prompt appeared for a second and the screen went black for a second or two, then the image returned but distorted beyond recognition. In another second or two the screen went black again and then distorted image again. This was a continious loop. I could not use CTRL+ALT+F1 etc to go to command prompt so rebooted the machine. When unity greeter launched it went into the same loop as described above not allowing me to type the password (it had the second account which I wanted to use highlighted and did not allow me enough time to even move to the first one).

How was the problem resolved:
- I physically removed the Nvidia video adapter from the PC. Used the built in Intel adapter instead. This allowed me few seconds to select the first account which i usualy use and type the password. On shutting down the PC and fitting back the Nvidia adapter everithing went back to normal and the bug reporting prompt appeared after log on with the original (first) user account.

ProblemType: Crash
DistroRelease: Ubuntu 12.04
Package: unity-greeter 0.2.5-0ubuntu1
ProcVersionSignature: Ubuntu 3.2.0-19.30-generic 3.2.11
Uname: Linux 3.2.0-19-generic x86_64
NonfreeKernelModules: nvidia
ApportVersion: 1.94.1-0ubuntu2
Architecture: amd64
Date: Sun Mar 18 23:26:14 2012
ExecutablePath: /usr/sbin/unity-greeter
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Alpha amd64 (20120201.2)
ProcCmdline: /usr/sbin/unity-greeter
ProcEnviron:
 LANGUAGE=en_GB:en
 LANG=en_GB.UTF-8
 SHELL=/bin/false
SegvAnalysis:
 Segfault happened at: 0x40aff0: mov %eax,0x3c(%rdx)
 PC (0x0040aff0) ok
 source "%eax" ok
 destination "0x3c(%rdx)" (0xaaaaaaaaaaaaaae6) not located in a known VMA region (needed writable region)!
 Stack memory exhausted (SP below stack segment)
SegvReason: writing unknown VMA
Signal: 11
SourcePackage: unity-greeter
StacktraceTop:
 ?? ()
 ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
 start_thread () from /lib/x86_64-linux-gnu/libpthread.so.0
 clone () from /lib/x86_64-linux-gnu/libc.so.6
 ?? ()
Title: unity-greeter crashed with SIGSEGV in start_thread()
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups:

mtime.conffile..etc.lightdm.unity.greeter.conf: 2012-02-10T00:37:11.014045

[Apport retracing service (apport)]

Thank you for taking the time to report this crash and helping to make this software better. This particular crash has already been reported and is a duplicate of bug #942227, so is being marked as such. Please look at the other bug report to see if there is any missing information that you can provide, or to see if there is a workaround for the bug. Additionally, any further discussion regarding the bug should occur in the other report. Please continue to report any other bugs you may find.