[tbb-bugs] #21838 [Applications/Tor Browser]: Gitian VM creation fails on Ubuntu 16.x machines in the unmount step

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#21838: Gitian VM creation fails on Ubuntu 16.x machines in the unmount step
------------------------------------------+------------------------
     Reporter:  gk                        |      Owner:  tbb-team
         Type:  defect                    |     Status:  new
     Priority:  Medium                    |  Milestone:
    Component:  Applications/Tor Browser  |    Version:
     Severity:  Normal                    |   Keywords:  tbb-gitian
Actual Points:                            |  Parent ID:
       Points:                            |   Reviewer:
      Sponsor:                            |
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 There have been reports that creating Gitian VMs on Ubuntu 16.x machines
 fails with error messages like:
 {{{
 2016-10-06 15:11:05,650 INFO    : umount: /tmp/tmpxmUBiv/: target is busy
 2016-10-06 15:11:05,651 INFO    :         (In some cases useful info about
 processes that
 2016-10-06 15:11:05,651 INFO    :          use the device is found by
 lsof(8) or fuser(1).)
 2016-10-06 15:11:05,651 ERROR   : Process (['umount', '/tmp/tmpxmUBiv/'])
 returned 32. stdout: , stderr: umount: /tmp/tmpxmUBiv/: target is busy
         (In some cases useful info about processes that
          use the device is found by lsof(8) or fuser(1).)

 Traceback (most recent call last):
   File "/usr/local/bin/vmbuilder", line 24, in <module>
     cli.main()
   File "/usr/local/lib/python2.7/dist-packages/VMBuilder/contrib/cli.py",
 line 228, in main
     hypervisor.install_os()
   File "/usr/local/lib/python2.7/dist-packages/VMBuilder/hypervisor.py",
 line 70, in install_os
     self.call_hooks('install_bootloader', self.chroot_dir, self.disks)
   File "/usr/local/lib/python2.7/dist-packages/VMBuilder/distro.py", line
 69, in call_hooks
     self.cleanup()
   File "/usr/local/lib/python2.7/dist-packages/VMBuilder/distro.py", line
 44, in cleanup
     self._cleanup_cbs.pop(0)()
   File "/usr/local/lib/python2.7/dist-packages/VMBuilder/disk.py", line
 409, in umount
     run_cmd('umount', self.mntpath)
   File "/usr/local/lib/python2.7/dist-packages/VMBuilder/util.py", line
 120, in run_cmd
     raise VMBuilderException, "Process (%s) returned %d. stdout: %s,
 stderr: %s" % (args.__repr__(), status, mystdout.buf, mystderr.buf)
 VMBuilder.exception.VMBuilderException: Process (['umount',
 '/tmp/tmpxmUBiv/']) returned 32. stdout: , stderr: umount:
 /tmp/tmpxmUBiv/: target is busy
         (In some cases useful info about processes that
          use the device is found by lsof(8) or fuser(1).)

 qemu-img: target-wheezy-i386.qcow2: Could not open 'base-
 wheezy-i386.qcow2': No such file or directory
 i386 wheezy VM creation failed
 }}}

 And, indeed, for some reason there seem to be still resources used:
 {{{
 /dev/dm-12 on /tmp/tmp9k2g2E type ext3 (rw,relatime,data=ordered)
 /dev/sda1 on /tmp/tmp9k2g2E/tmp/vmbuilder-grub/tmpUE0GzK type ext4
 (rw,relatime,errors=remount-ro,data=ordered)
 }}}

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/21838>
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