Re: Bug#732937: dpkg: fails somewhat regularly on kfreebsd-amd64

[Guillem Jover <guillem@debian.org>]

Hi!

On Sun, 2013-12-22 at 21:53:19 +0100, Axel Beckert wrote:
> Michael Gilbert wrote:
> > dpkg seems to often fail on kfreebsd-amd64 on unstable (I had not
> > experienced this with wheezy).
> 
> I can confirm that for kfreebsd-i386.

Ok, this is something new, I had not seen it before, but I can see
it being broken only when using apt. The same command using dpkg
directly works fine.

I can reproduce it with simply running:

  $ apt-get install --reinstall git

> > The error message is
> > 
> > E: Sub-process /usr/bin/dpkg returned an error code (1)
> 
> Yeah, and noting else. It's not clear, why there was an error.

The problem is that something messes with dpkg's standard output and
error, and it fails when doing the fflush() and ferror() check on it
in m_output() I think. But this seems to be coming from something
lower than dpkg or apt, perhaps a change in glibc or the kernel. As
I've tried with downgraded versions matching the ones in stable, and
it still fails. I've not tested further.

The last thing reported from dpkg to apt through the status-fd channel
is:

  status: git : error : error writing to '<standard output>': No such file or directory

and then dpkg exits “normally” after proceeding with the error
unwinding cleanup.

> > This is easily recoverable by running the command a second time, which
> > usually succeeds.
> 
> Yeah, but it often needs multiple tries though. I usually run
> "aptitude install -y || aptitude install -y || aptitude install -y"
> or such after I saw such a failure.

Ouch.

Thanks,
Guillem