Comment 21 for bug 1381170

Here is gnu parted output with mdadm installed and configured.
mint@mint ~ $ sudo parted
GNU Parted 2.3
Using /dev/sda
Welcome to GNU Parted! Type 'help' to view a list of commands.
(parted) exit
  align-check TYPE N check partition N for TYPE(min|opt)
        alignment
  check NUMBER do a simple check on the file system
  cp [FROM-DEVICE] FROM-NUMBER TO-NUMBER copy file system to another partition
  help [COMMAND] print general help, or help on
        COMMAND
  mklabel,mktable LABEL-TYPE create a new disklabel (partition
        table)
  mkfs NUMBER FS-TYPE make a FS-TYPE file system on
        partition NUMBER
  mkpart PART-TYPE [FS-TYPE] START END make a partition
  mkpartfs PART-TYPE FS-TYPE START END make a partition with a file system
  resizepart NUMBER END resize partition NUMBER
  move NUMBER START END move partition NUMBER
  name NUMBER NAME name partition NUMBER as NAME
  print [devices|free|list,all|NUMBER] display the partition table,
        available devices, free space, all found partitions, or a particular
        partition
  quit exit program
  rescue START END rescue a lost partition near START
        and END
  resize NUMBER START END resize partition NUMBER and its file
        system
  rm NUMBER delete partition NUMBER
  select DEVICE choose the device to edit
  set NUMBER FLAG STATE change the FLAG on partition NUMBER
  toggle [NUMBER [FLAG]] toggle the state of FLAG on partition
        NUMBER
  unit UNIT set the default unit to UNIT
  version display the version number and
        copyright information of GNU Parted
(parted) print
Error: Invalid argument during seek for read on /dev/sda
Retry/Ignore/Cancel? i
Error: The backup GPT table is corrupt, but the primary appears OK, so that will
be used.
OK/Cancel? ok
Backtrace has 8 calls on stack:
  8: /lib/x86_64-linux-gnu/libparted.so.0(ped_assert+0x31) [0x7f0fe89a34b1]
  7: /lib/x86_64-linux-gnu/libparted.so.0(+0x3f5f6) [0x7f0fe89d35f6]
  6: /lib/x86_64-linux-gnu/libparted.so.0(ped_disk_new+0x49) [0x7f0fe89a8f99]
  5: parted() [0x406dff]
  4: parted(interactive_mode+0x101) [0x40db71]
  3: parted(main+0x153d) [0x4065bd]
  2: /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xf5) [0x7f0fe8181ec5]
  1: parted() [0x406617]

You found a bug in GNU Parted! Here's what you have to do:

Don't panic! The bug has most likely not affected any of your data.
Help us to fix this bug by doing the following:

Check whether the bug has already been fixed by checking
the last version of GNU Parted that you can find at:

 http://ftp.gnu.org/gnu/parted/

Please check this version prior to bug reporting.

If this has not been fixed yet or if you don't know how to check,
please visit the GNU Parted website:

 http://www.gnu.org/software/parted

for further information.

Your report should contain the version of this release (2.3)
along with the error message below, the output of

 parted DEVICE unit co print unit s print

and the following history of commands you entered.
Also include any additional information about your setup you
consider important.

Assertion (last_usable <= disk->dev->length) at
../../../libparted/labels/gpt.c:994 in function _parse_header() failed.