gdm-session-worker crashed with SIGSEGV in add_user()

[Ryan Tandy]

This system boots from NFS (/ on aufs) and uses lib{pam,nss}-ldapd for authentication.

After entering the username and password and pressing Login, most times the login window goes to the busy state (buttons disabled, cursor spinning) and hangs there forever. Sometimes (once in four, maybe?) it just works.

In the default gdm configuration, no crash or error is recorded. With /etc/gdm/custom.conf:

[debug]
Enabled=true

I get the attached crash. I will see if I can get this to happen on a system with a more conventional configuration...

ProblemType: Crash
DistroRelease: Ubuntu 12.04
Package: gdm 3.0.4-0ubuntu15.1
ProcVersionSignature: Ubuntu 3.8.0-33.48~precise1-generic 3.8.13.11
Uname: Linux 3.8.0-33-generic i686
NonfreeKernelModules: nvidia
ApportVersion: 2.0.1-0ubuntu17.6
Architecture: i386
Date: Fri Nov 22 11:41:17 2013
ExecutablePath: /usr/lib/gdm/gdm-session-worker
ExecutableTimestamp: 1365672668
MarkForUpload: True
ProcCmdline: /usr/lib/gdm/gdm-session-worker
ProcCwd: /
ProcEnviron:
 LANG=en_CA.UTF-8
 TERM=linux
 LANGUAGE=en_CA:
 PATH=(custom, no user)
SegvAnalysis:
 Segfault happened at: 0xb7428160 <malloc_consolidate+256>: mov 0x4(%edi),%edx
 PC (0xb7428160) ok
 source "0x4(%edi)" (0xc0f64c9c) not located in a known VMA region (needed readable region)!
 destination "%edx" ok
SegvReason: reading unknown VMA
Signal: 11
SourcePackage: gdm
StacktraceTop:
 add_user (user=0x99f2d50, manager=0x99f3820) at act-user-manager.c:698
 on_new_user_loaded (manager=0x99f3820, user=0x99f2d50, pspec=<optimized out>) at act-user-manager.c:822
 on_new_user_loaded (user=0x99f2d50, pspec=0x99eb0f0, manager=0x99f3820) at act-user-manager.c:766
 g_cclosure_marshal_VOID__PARAM (closure=0x99ed480, return_value=0x0, n_param_values=2, param_values=0xbfa28700, invocation_hint=0xbfa28680, marshal_data=0x0) at /build/buildd/glib2.0-2.32.4/./gobject/gmarshal.c:1042
 g_closure_invoke (closure=0x99ed480, return_value=0x0, n_param_values=2, param_values=0xbfa28700, invocation_hint=0xbfa28680) at /build/buildd/glib2.0-2.32.4/./gobject/gclosure.c:777
Title: gdm-session-worker crashed with SIGSEGV in add_user()
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups:

[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 #854474, 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.