debconf segfault during upgrade (was: Gutsy upgrade path from feisty fails (update-manager))

strace

it seems to be related to having feisty-backports enabled in /etc/apt/sources.list

changing contents of /etc/apt/sources.list to

--
deb http://security.ubuntu.com/ubuntu gutsy-security main restricted
deb-src http://security.ubuntu.com/ubuntu gutsy-security main restricted
deb http://security.ubuntu.com/ubuntu gutsy-security universe
deb-src http://security.ubuntu.com/ubuntu gutsy-security universe
deb http://security.ubuntu.com/ubuntu gutsy-security multiverse
deb-src http://security.ubuntu.com/ubuntu gutsy-security multiverse
deb http://archive.ubuntu.com/ubuntu/ gutsy main
 --

and re-running update-manager seems to fix the issue

Thanks for taking the time to report this bug and helping to make Ubuntu better. Could you please add the log files from '/var/log/dist-upgrade/' to this bugreport as attachments to your bug report? Thanks in advance.

Preparing to replace libpam0g 0.79-4ubuntu2 (using .../libpam0g_0.99.7.1-5ubuntu1_i386.deb) ...
Unpacking replacement libpam0g ...
.9.1-6ubuntu4_i386.deb) ...
Setting up libpam0g (0.99.7.1-5ubuntu1) ...
Checking for services that may need to be restarted...
Checking for services that may need to be restarted...Checking init scripts...
/usr/lib/libgdk-x11-2.0.so.0[0xb712306f]
/usr/lib/libgdk-x11-2.0.so.0(gdk_window_process_all_updates+0xba)[0xb712373a]
/usr/lib/libgtk-x11-2.0.so.0[0xb7235d8f]
/usr/lib/libgdk-x11-2.0.so.0[0xb71095e8]
/usr/lib/libglib-2.0.so.0[0xb7aff551]
/usr/lib/libglib-2.0.so.0(g_main_context_dispatch+0x17c)[0xb7b0111c]
/usr/lib/libglib-2.0.so.0[0xb7b0455f]
/usr/lib/libglib-2.0.so.0(g_main_loop_run+0x1a9)[0xb7b04909]
/usr/lib/libgtk-x11-2.0.so.0(gtk_main+0xb4)[0xb72cd9e4]
/usr/lib/perl5/auto/Gtk2/Gtk2.so(XS_Gtk2_main+0x91)[0xb75e7ab1]
/usr/bin/perl(Perl_pp_entersub+0x3ab)[0x80c23cb]
/usr/bin/perl(Perl_runops_standard+0x19)[0x80c0d29]
======= Memory map: ========
08048000-0814c000 r-xp 00000000 03:01 4161793 /usr/bin/perl
0814c000-08150000 rw-p 00103000 03:01 4161793 /usr/bin/perl
08150000-09052000 rw-p 08150000 00:00 0 [heap]
b5400000-b5421000 rw-p b5400000 00:00 0
b5421000-b5500000 ---p b5421000 00:00 0
b5627000-b5fdb000 r--p 00000000 03:01 5162433 /usr/share/icons/hicolor/icon-theme.cache
b5fdb000-b6694000 r--p 00000000 03:01 5162432 /usr/share/icons/gnome/icon-theme.cache
b6694000-b6718000 r--p 00000000 03:01 4997185 /usr/share/fonts/truetype/ttf-dejavu/De
b6694000-b6718000 r--p 00000000 03:01 4997185 /usr/share/fonts/truetype/ttf-dejavu/De/usr/share/debconf/confmodule: line 42: printf: write error: Broken pipe
GET libpam0g/restart-services
dpkg: error processing libpam0g (--configure):
 subprocess post-installation script killed by signal (Aborted), core dumped
Errors were encountered while processing:
 libpam0g

Yeah I have too. It started with Debconf stalling, but then I kept getting more and more errors. The upgrading said that it will nonetheless continue. But now I think it has stalled on "configuring zlip1g". The GUI still works partly, but I can't get the Terminal to show. Also when the updater tells I can report a bug, it tries to load up Konqueror, but nothing really happens...

And yeah, Kubuntu is the distribution!

Same here, log shows segfaults. I noticed the exact same behavior that Toni noted, though mine is stalled on 'libaa1'.
Kubuntu Feisty to Gutsy, with fairly minimal extra packages/repositories.

I might add that Kubuntu's upgrade HAS never worked! I manage a number of PC (ok, less than 10 though :) ), but even the stock ones does never upgrade completely. It always stalls. Whether it was Edgy -> Feisty or Feisty -> Gutsy. It hasn't worked. It even works in Xubuntu which at least earlier wasn't even an official release. And my goal was to install these Kubuntu's to everyday use with non-computer-literate people. But an admin is needed to upgrade them, always, or the system is left unusable...