Comment 18 for bug 442941

Aha! What appears to be happening is that the installer erroneously sets up /var/cache/debconf/config.dat with mode 0600, so it's unreadable to the user-mode debconf frontend, which falls over and leaves the root debconf proxy without anything to talk to; it then crashes shortly afterwards and we're left with this horrendous mess to try to debug. This explains Amael's comment #8, and other comments indicating that this goes away after the first upgrade.

I can fix this in the installer, but of course that only applies for future releases. For current releases, we have pretty limited options here. The only way we can push out code to fix the permissions is to release a package to -updates that does it, but in this case the user-mode debconf frontend is started up (and fails) before we install any packages, so that's likely to be ineffective.

After some discussion on #ubuntu-devel, it seems that the least bad of the available options is to write a wiki page documenting the problem and a workaround (and probably also documenting the similar problem in bug 500175, since I don't think we can tell the two problems apart automatically - I've just gone through several dozen of the duplicate bug reports and I'm not even sure I can tell them apart manually), and cause people with this problem to be redirected to that bug report rather than filing a new bug. This should go some way towards explaining what's going on, and things should be fixed up on their next upgrade in any case. We'll then make sure that initial installations of Oneiric won't have this bug.