ubuntu-emulator create fails for devel-proposed: Failed to unmount temp dir where system image was created

[Martin Pitt]

In current vivid at least, I can't build an emulator for devel-proposed any more:

$ sudo ubuntu-emulator create --channel=ubuntu-touch/devel-proposed dprop
Creating "dprop" from ubuntu-touch/devel-proposed revision 107
Downloading...
2.24 MB / 2.24 MB [========================================================================================] 100.00 % 823.05 KB/s
349.67 MB / 349.67 MB [======================================================================================] 100.00 % 2.45 MB/s
Setting up...
Setting up a default password for phablet to: '0000'
Failed to unmount temp dir where system image was created

I don't actually have any leftover mounts, just this directory in /tmp/:

drwx------ 23 root martin 600 Feb 19 07:37 ubuntu-system039784550

Creating an emulator from the "devel" channel still works. (But I guess not for long any more, once devel-proposed gets promoted).

ProblemType: Bug
DistroRelease: Ubuntu 15.04
Package: ubuntu-emulator 0.16-0ubuntu1
ProcVersionSignature: Ubuntu 3.18.0-13.14-generic 3.18.5
Uname: Linux 3.18.0-13-generic x86_64
ApportVersion: 2.16.1-0ubuntu2
Architecture: amd64
CurrentDesktop: Unity
Date: Thu Feb 19 07:44:55 2015
EcryptfsInUse: Yes
InstallationDate: Installed on 2014-11-20 (90 days ago)
InstallationMedia: Ubuntu 15.04 "Vivid Vervet" - Alpha amd64 (20141119)
SourcePackage: goget-ubuntu-touch
UpgradeStatus: No upgrade log present (probably fresh install)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Timo Jyrinki (timo-jyrinki)]

For me, the creation failed with:
---
351.43 MB / 351.43 MB [========================================================================================] 100.00 % 1.41 MB/s
Setting up...
Setting up a default password for phablet to: '0000'
open /tmp/ubuntu-system872087212/build.prop: permission denied
---
And I had only empty /tmp/ubuntu-system902863095/ (different number).

The emulator is "created", but running it gives:
open /home/timo/.local/share/ubuntu-emulator/test/.device: no such file or directory

[Ricardo Salveti (rsalveti)]

This actually smells something with systemd, as I just noticed that the original issue is that the mount point gets unmounted right after it gets mounted by ubuntu-emulator.

rsalveti@evasys:/tmp/sergio$ sudo ubuntu-emulator create --channel=ubuntu-touch/vivid-proposed test_x86 --use-raw-disk
Creating "test_x86" from ubuntu-touch/vivid-proposed revision 138
Downloading...
Setting up...
Mount: calling: mount /home/rsalveti/.local/share/ubuntu-emulator/test_x86/ubuntu-system.img /tmp/ubuntu-system364514705

And from syslog:
Mar 16 19:17:06 evasys systemd[2918]: Unit tmp-ubuntu\x2dsystem364514705.mount is bound to inactive unit. Stopping, too.
Mar 16 19:17:06 evasys systemd[1]: Unit tmp-ubuntu\x2dsystem364514705.mount is bound to inactive unit. Stopping, too.
Mar 16 19:17:06 evasys systemd[1]: Unmounting /tmp/ubuntu-system364514705...
Mar 16 19:17:06 evasys systemd[2918]: Unmounting /tmp/ubuntu-system364514705...
Mar 16 19:17:06 evasys kernel: [55815.378380] EXT4-fs (loop0): mounted filesystem with ordered data mode. Opts: (null)
Mar 16 19:17:06 evasys systemd[1]: Requested transaction contradicts existing jobs: Resource deadlock avoided
Mar 16 19:17:06 evasys umount[27719]: umount: /tmp/ubuntu-system364514705: not mounted
Mar 16 19:17:06 evasys systemd[2918]: tmp-ubuntu\x2dsystem364514705.mount mount process exited, code=exited status=1
Mar 16 19:17:06 evasys systemd[2918]: Unmounted /tmp/ubuntu-system364514705.
Mar 16 19:17:06 evasys systemd[2918]: Unit tmp-ubuntu\x2dsystem364514705.mount entered failed state.
Mar 16 19:17:06 evasys systemd[1]: Unmounted /tmp/ubuntu-system364514705.

Same happens when I try to manually mount the system image. And which is interesting because mount actually works fine, not giving any error, but then systemd just unmount it right away.

[Ricardo Salveti (rsalveti)]

Same issue also described at https://bugs.gentoo.org/show_bug.cgi?id=541402

It is indeed a different behavior with systemd, where it tries to control the calls to 'mount'.

[Ricardo Salveti (rsalveti)]

A small workaround that allows creating the emulator image again (as systemd will ignore the mount point if you mount a tmpfs at the same spot first).

$ bzr diff
=== modified file 'diskimage/image.go'
--- diskimage/image.go 2015-01-21 23:22:53 +0000
+++ diskimage/image.go 2015-03-16 23:28:01 +0000
@@ -107,6 +107,9 @@
   }
  }()

+ if out, err := exec.Command("mount", "-t", "tmpfs", "none", img.Mountpoint).CombinedOutput(); err != nil {
+ return fmt.Errorf("unable to mount temp dir to create system image: %s", out)
+ }
  if out, err := exec.Command("mount", img.path, img.Mountpoint).CombinedOutput(); err != nil {
   return fmt.Errorf("unable to mount temp dir to create system image: %s", out)
  }
@@ -126,6 +129,9 @@
  if err := exec.Command("umount", img.Mountpoint).Run(); err != nil {
   return errors.New("Failed to unmount temp dir where system image was created")
  }
+ if err := exec.Command("umount", img.Mountpoint).Run(); err != nil {
+ return errors.New("Failed to unmount temp dir where system image was created")
+ }
  return nil
 }

[Martin Pitt (pitti)]

Hey Ricardo,

the "unmounted due to inactive unit" was fixed upstream recently. I can backport these after my holidays.
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[dinamic (dinamic6661)]

same here on Ubuntu 15.04 http://i.imgur.com/O5kwPZd.png

[dinamic (dinamic6661)]

Creating "test" from devel-proposed revision 145
Downloading...
...
Setting up...

Setting up a default password for phablet to: '0000'

Failed to unmount temp dir where system image was created

[Ricardo Salveti (rsalveti)]

Fixed with systemd 219-4ubuntu10