[Bug 1311247] [grub2/trusty] possible regression found

[Ubuntu Foundations Team Bug Bot]

As a part of the Stable Release Updates quality process a search for
Launchpad bug reports using the version of grub2 from trusty-proposed
was performed and bug 1507175 was found.  Please investigate this bug
report to ensure that a regression will not be created by this SRU. In
the event that this is not a regression remove the "verification-failed"
tag from this bug report and add the tag "bot-stop-nagging" to bug
1507175 (not this bug). Thanks!

** Tags added: verification-failed

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https://bugs.launchpad.net/bugs/1311247

Title:
  [Grubenv] error: malformed file, press any key to continue

Status in grub:
  Unknown
Status in grub2 package in Ubuntu:
  Fix Released
Status in grub2-signed package in Ubuntu:
  Fix Released
Status in grub2 source package in Trusty:
  Fix Committed
Status in grub2-signed source package in Trusty:
  Fix Committed

Bug description:
  [Impact]

  Some users with specific partitioning schemes may see a grub error
  message interrupting boot:

  "error: malformed file, press any key to continue"

  It appears to be caused by an invalid check for block overlap in
  grub2, and only applies to very specific installs, mostly using ext4,
  possibly limited to recent kernel versions.

  [Test Case]

  On an affected system, try to reboot the system.

  [Regression Potential]

  This is a fix which has been applied upstream for over a year, and
  included in 15.04. It changes comparisons in start and end values for
  block numbers to correctly match overlapping lists, and therefore
  should not affect more typical partitioning where there is no overlap.
  In effect, this changes increases the number of cases where a
  blocklist is deemed valid without removing the formerly accepted
  states, when loading the environment block.

  A possible regression might show up as grub being unable to retrieve
  its last state for boot (ie. which menu entry was selected last time),
  but still successfully booting.

  --

  I have just upgraded from 12.04 to 14.04

  Since the upgrade, when I boot up, the process stops and the normal
  grub screen is replaced after a short while by a message saying

  "error: malformed file, press any key to continue"

  Pressing a key allows booting to continue.

  Someone else who experienced this found that the problem went away
  after having re-installed grub. I tried this but this did not resolve
  the problem for me.

  synaptic reports the grub package as 2.02~beta2-9

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