Preseeded 12.04 grub-install failed: Wrong number of args: mapdevfs <path>

Bug #912431 reported by Adam Gandelman on 2012-01-05
This bug affects 4 people
Affects Status Importance Assigned to Milestone
debian-installer-utils (Ubuntu)
Colin Watson
grub-installer (Ubuntu)

Bug Description

Using the latest precise amd64 mini.iso, grub-install has recently started to fail on preseeded installations. The preseeds have remained pretty static relative to mini.iso updates. I"m not sure this is directly related to grub-installer as there hasn't been an upload in ~12 weeks, but I am unsure where else to file this.

After failure, grub-install reports the following in syslog (also attached):

Jan 5 18:19:21 in-target: grub-common is already the newest version.
Jan 5 18:19:21 in-target: 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
Jan 5 18:19:21 main-menu[494]: (process:27699): Wrong number of args: mapdevfs <path>
Jan 5 18:19:21 main-menu[494]: WARNING **: Configuring 'grub-installer' failed with error code 1
Jan 5 18:19:21 main-menu[494]: WARNING **: Menu item 'grub-installer' failed.

Adam Gandelman (gandelman-a) wrote :
Adam Gandelman (gandelman-a) wrote :
Adam Gandelman (gandelman-a) wrote :
Adam Gandelman (gandelman-a) wrote :
Serge Hallyn (serge-hallyn) wrote :

Same here, both with and without pre-seeds. Marking confirmed.

rebooting from the cd in rescue mode and doing 'apt-get install grub2' lets me proceed.

Changed in grub-installer (Ubuntu):
status: New → Confirmed
importance: Undecided → High
Andres Rodriguez (andreserl) wrote :

Attaching syslog with debconf debug output

Changed in grub-installer (Ubuntu):
assignee: nobody → Canonical Foundations Team (canonical-foundations)

We have this problem too. The fix is in grub-installer in the udeb.

The problem is the grub_probe function in that script. It does an apt-install and then calls grub-probe in the chroot. The apt-install prints output, however, and the callers of grub_probe expect to see only the output from grub-probe itself. As a result, output from apt-install is slammed into the variables which later become the arguments to mapdevfs.

If you do 2>&1 > /dev/null after the apt-install in that function, the install proceeds without a problem.

Scott Moser (smoser) wrote :

It seems to me that this is a regression caused by most recent update of debian-installer-utils that started using dpkg-divert rather than mv to manage start-stop-daemon.

So I would guess the simplist fix here is to just make dpkg-divert quiet.

I've submitted merge proposal at .

Scott Moser (smoser) on 2012-01-06
Changed in debian-installer-utils (Ubuntu):
importance: Undecided → High
status: New → Confirmed
Colin Watson (cjwatson) on 2012-01-06
Changed in grub-installer (Ubuntu):
status: Confirmed → Invalid
assignee: Canonical Foundations Team (canonical-foundations) → nobody
Changed in debian-installer-utils (Ubuntu):
assignee: nobody → Colin Watson (cjwatson)
status: Confirmed → Triaged
Colin Watson (cjwatson) wrote :

Agreed - chroot_setup must be silent. Thanks, Scott!

Launchpad Janitor (janitor) wrote :

This bug was fixed in the package debian-installer-utils - 1.88ubuntu2

debian-installer-utils (1.88ubuntu2) precise; urgency=low

  [ Scott Moser ]
  * Add --quiet to dpkg-divert calls in chroot_setup (LP: #912431).
 -- Colin Watson <email address hidden> Fri, 06 Jan 2012 12:19:21 +0000

Changed in debian-installer-utils (Ubuntu):
status: Triaged → Fix Released

I'm confused about why chroot_setup is the issue here. It's the apt-install command inside the grub_probe command which is spitting out output, and the output it spits out looks like typical apt-get output.

On Fri, Jan 06, 2012 at 05:44:28PM -0000, Thomas Bushnell, BSG wrote:
> I'm confused about why chroot_setup is the issue here. It's the apt-
> install command inside the grub_probe command which is spitting out
> output, and the output it spits out looks like typical apt-get output.

apt-install uses chroot_setup, via in-target. The apt-get output goes
to stderr (due to 'debconf-apt-progress --logstderr') and thence to
syslog and doesn't interfere with grub_probe. By contrast, the
dpkg-divert output went to stdout.

Besides, chroot_setup is the only thing anywhere around here that
changed recently; I'd have guessed at that myself if Scott hadn't beaten
me to it!

Just did a fresh text install (twice) of 14.04 and the install grub step failed with exactly the same symptoms. Trying to do things manually results in a boot where I get dumped into initramfs

Colin Watson (cjwatson) wrote :

I need fresh installer logs and a copy of the preseed file, please,
preferably in a fresh bug report; it can often be the case that quite
different underlying causes present with the same symptoms. Feel free
to explicitly subscribe me to the new bug so that I see it.

TJ (tj) wrote :

@Roger Binns: your issue may (have) been caused by bug #1354730

Changed in grub-installer (Ubuntu):
status: Invalid → Incomplete
Colin Watson (cjwatson) on 2018-02-26
Changed in grub-installer (Ubuntu):
status: Incomplete → Invalid
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