install writes /etc/mtab as file, not symlink

Bug #1511376 reported by Kev Bowring on 2015-10-29
This bug affects 8 people
Affects Status Importance Assigned to Milestone
finish-install (Debian)
Fix Released
finish-install (Ubuntu)
ubiquity (Ubuntu)
Martin Pitt
Martin Pitt

Bug Description

Updated iso to today's daily for installing.

Installed to a preformatted partition.

Xubuntu 64bit desktop install.

Install completed, rebooted. Stopped at

/etc/mtab is not a symlink or not pointing to /proc/self/mounts

Booted to recovery:

ln -fs /proc/self/mounts /etc/mtab

Rebooted and system booted as expected.

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: ubiquity (not installed)
ProcVersionSignature: Ubuntu 4.2.0-16.19-generic 4.2.3
Uname: Linux 4.2.0-16-generic x86_64
ApportVersion: 2.19.2-0ubuntu1
Architecture: amd64
CurrentDesktop: XFCE
Date: Thu Oct 29 13:35:07 2015
InstallationDate: Installed on 2015-10-29 (0 days ago)
InstallationMedia: Xubuntu 16.04 LTS "Xenial Xerus" - Alpha amd64 (20151029)
SourcePackage: ubiquity
UpgradeStatus: No upgrade log present (probably fresh install)

Related branches

Kev Bowring (flocculant) wrote :
Martin Pitt (pitti) wrote :

See for more information why we currently have such a hard failure mode and the rationale behind it.

Changed in ubiquity (Ubuntu):
status: New → Triaged
importance: Undecided → High
summary: - /etc/mtab is not a link
+ ubiquity install writes /etc/mtab as file, not symlink
Changed in ubiquity (Ubuntu Xenial):
assignee: nobody → Martin Pitt (pitti)
summary: - ubiquity install writes /etc/mtab as file, not symlink
+ install writes /etc/mtab as file, not symlink
Martin Pitt (pitti) wrote :

We need to merge with Debian's finish-install 2.58 to fix d-i.

Changed in finish-install (Ubuntu Xenial):
status: New → Triaged
Martin Pitt (pitti) wrote :
Changed in finish-install (Ubuntu Xenial):
status: Triaged → Fix Released
Ubuntu QA Website (ubuntuqa) wrote :

This bug has been reported on the Ubuntu ISO testing tracker.

A list of all reports related to this bug can be found here:

tags: added: iso-testing
Changed in finish-install (Debian):
status: Unknown → Fix Released
Martin Pitt (pitti) on 2015-10-29
Changed in ubiquity (Ubuntu Xenial):
milestone: none → ubuntu-15.11
sudodus (nio-wiklund) wrote :

This bug affects Lubuntu i386 too.

I'm glad to see that a fix is already released :-)

Martin Pitt (pitti) on 2015-10-29
Changed in ubiquity (Ubuntu Xenial):
status: Triaged → In Progress
Martin Pitt (pitti) wrote :

Note from Colin: Do that in scripts/ run(), which already has a bunch of ad-hoc finalization tasks.

Phill Whiteside (phillw) wrote :

If running on a VM and you have guestfish installed, you can make the link using it. Close the VM down

sudo guestfish --rw -a disk.img
mount /dev/sda1 /
ln-sf /proc/self/mounts /etc/mtab

Then re-start the VM. Do note that the command is 'ln-sf' and not 'ln -sf'... that had me scratching my head for a while!

sudodus (nio-wiklund) wrote :

Running in a *real* computer I booted from the install pendrive, changed directory to the mounted partition of the installed system and ran

sudo ln -sf /proc/self/mounts etc/mtab

(ln {space} -sf and no slash before etc works in this case)

And, yes, now I can continue to test Lubuntu Xenial. The installed system boots and runs well.

Thanks Phill :-)

Martin Pitt (pitti) on 2015-11-02
Changed in ubiquity (Ubuntu Xenial):
status: In Progress → Fix Committed
Launchpad Janitor (janitor) wrote :

This bug was fixed in the package ubiquity - 2.21.38

ubiquity (2.21.38) xenial; urgency=medium

  * d-i/sources.list: switch to xenial.
  * scripts/ Ensure /etc/mtab is a symlink to
    /proc/self/mounts. Same fix as in finish-install 2.58.
    (Closes: #802184, #802187; LP: #1511376)
  * Automatic update of included source packages: choose-mirror
    2.65ubuntu1, partman-lvm 111.

 -- Martin Pitt <email address hidden> Sun, 01 Nov 2015 21:21:28 -0600

Changed in ubiquity (Ubuntu Xenial):
status: Fix Committed → Fix Released

I seem to have ran into this issue on the very first boot after a fresh install of Ubuntu Server 15.10 on nuc5ppyh. See

More details from another user having similar issues --

My apologies in advance if these issues are not exactly related to this bug. I just want to provide as much info as I can.

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