[Debconf-devel] Bug#439763: debconf: hangs on puppet installs on preseed install

[John Morrissey]

On Tue, Dec 18, 2007 at 05:16:03PM +0000, Colin Watson wrote:
> On Mon, Aug 27, 2007 at 10:42:41AM +0100, Adrian Bridgett wrote:
> > When postfix.config runs /usr/share/debconf/confmodules, at line 45 it
> > complains that FD3 is a bad file descriptor.  Listing /proc/$$/fd
> > shows that FD3 doesn't exist.  FD2 points to the overall stderr, FD1
> > is a pipe back to FD8 of dpkg-preconfigure.  FD0 is FD7 from
> > dpkg-preconfigure.
> > 
> > FD3 exists and DEBCONF_REDIR is set when ConfModule::startup() is
> > called, however it looks like FD3 does not persist into the open2()
> > call.
> 
> On the other hand, it might be something completely different. I note
> that both sysstat and postfix call db_stop. I don't think this should
> actually break the cdebconf instance way down at the bottom of the
> stack, but it's possible that it will confuse the debconf running
> debconf-apt-progress. If you could run the whole install under
> DEBCONF_DEBUG=developer (you did something like this earlier), then this
> might shed some light on exactly which debconf frontend is seeing what
> commands.
[snip]
> I think I'd rather figure out the underlying problem. It may be that we
> need to ignore db_stop in some circumstances.

I came across this with d-i wheezy beta1. I have a late_command that runs
Puppet in /target, and most package installations were failing due to EBADF
on fd3, mostly when handling man-db triggers. man-db.postinst fails when the
first db_* tries to write to fd3. Adding an lsof to man-db.postinst shows
that fd3 isn't present.

I can reproduce with something as simple as 'chroot /target apt-get -y
install php5-cli' in late_command.

I've posted the d-i syslog with DEBCONF_DEBUG=developer, late_command, and
env/lsof/strace output at http://horde.net/~jwm/debian/bug439763/ .

Could someone more knowledgable about debconf internals take a look at this,
please? I'm happy to help debug further, but I'm at a loss on how to
continue.

john
-- 
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