grub2 death when enter linux command twice

[dupingping]

Description: Ubuntu 14.04.3 LTS
Release: 14.04

grub2:
  Installed: (none)
  Candidate: 2.02~beta2-9ubuntu1.3
  Version table:
     2.02~beta2-9ubuntu1.3 0
        500 http://mirrors.yun-idc.com/ubuntu/ trusty-updates/universe amd64 Packages
     2.02~beta2-9 0
        500 http://mirrors.yun-idc.com/ubuntu/ trusty/universe amd64 Packages

I think that the grub2 needs to work for many grub shell commands.
But critical error is occurred as follow.

Bug scenario is as following.

- at the grub menu, press C key.
- enter "linux /vmlinuz" command to "grub>" shell
- enter above command once more.
- grub2 does not response.

I traced the code lines.
So the grub2 is entered and never ended a loop at the grub_core/lib/relocator.c, free_subchunk function.
And I could not skip this loop, because if i skip this loop, the /proc/cmdline is broken.

[dupingping (dupingping86)]

I checked this bug.

[Marcus Tomlinson (marcustomlinson)]

This release of Ubuntu is no longer receiving maintenance updates. If this is still an issue on a maintained version of Ubuntu please let us know.

[Launchpad Janitor (janitor)]

[Expired for grub2 (Ubuntu) because there has been no activity for 60 days.]