Comment 2 for bug 1512554

Confirmed. It still happens to me on Ubuntu 16.04 LTS amd64 with mdadm-3.3-2ubuntu7.2. I've also tried to upgrade to mdadm_3.4-4_amd64 from Zesty (https://launchpad.net/ubuntu/zesty/amd64/mdadm/3.4-4) with same results.

#> sudo mdadm --verbose --create /dev/md1 --level=mirror --raid-devices=2 --size=2790G --metadata=1.2 --name=startech-usb-enclosure-4bay-3Tb2 /dev/sdd /dev/sde
mdadm: automatically enabling write-intent bitmap on large array
*** buffer overflow detected ***: mdadm terminated
======= Backtrace: =========
/lib/x86_64-linux-gnu/libc.so.6(+0x777e5)[0x7fda092407e5]
/lib/x86_64-linux-gnu/libc.so.6(__fortify_fail+0x5c)[0x7fda092e211c]
/lib/x86_64-linux-gnu/libc.so.6(+0x117120)[0x7fda092e0120]
/lib/x86_64-linux-gnu/libc.so.6(+0x116472)[0x7fda092df472]
mdadm[0x433553]
mdadm[0x41c1d7]
mdadm[0x405951]
/lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xf0)[0x7fda091e9830]
mdadm[0x4085e9]
======= Memory map: ========
00400000-00476000 r-xp 00000000 08:06 655416 /sbin/mdadm
00675000-00676000 r--p 00075000 08:06 655416 /sbin/mdadm
00676000-0067d000 rw-p 00076000 08:06 655416 /sbin/mdadm
0067d000-00691000 rw-p 00000000 00:00 0
01cd2000-01cf3000 rw-p 00000000 00:00 0 [heap]
7fda08fb3000-7fda08fc9000 r-xp 00000000 08:06 1574085 /lib/x86_64-linux-gnu/libgcc_s.so.1
7fda08fc9000-7fda091c8000 ---p 00016000 08:06 1574085 /lib/x86_64-linux-gnu/libgcc_s.so.1
7fda091c8000-7fda091c9000 rw-p 00015000 08:06 1574085 /lib/x86_64-linux-gnu/libgcc_s.so.1
7fda091c9000-7fda09389000 r-xp 00000000 08:06 1577429 /lib/x86_64-linux-gnu/libc-2.23.so
7fda09389000-7fda09589000 ---p 001c0000 08:06 1577429 /lib/x86_64-linux-gnu/libc-2.23.so
7fda09589000-7fda0958d000 r--p 001c0000 08:06 1577429 /lib/x86_64-linux-gnu/libc-2.23.so
7fda0958d000-7fda0958f000 rw-p 001c4000 08:06 1577429 /lib/x86_64-linux-gnu/libc-2.23.so
7fda0958f000-7fda09593000 rw-p 00000000 00:00 0
7fda09593000-7fda095b9000 r-xp 00000000 08:06 1577305 /lib/x86_64-linux-gnu/ld-2.23.so
7fda09726000-7fda0975b000 r--s 00000000 08:06 1055715 /var/cache/nscd/group
7fda0975b000-7fda09790000 r--s 00000000 08:06 1055115 /var/cache/nscd/passwd
7fda09790000-7fda09793000 rw-p 00000000 00:00 0
7fda097b5000-7fda097b8000 rw-p 00000000 00:00 0
7fda097b8000-7fda097b9000 r--p 00025000 08:06 1577305 /lib/x86_64-linux-gnu/ld-2.23.so
7fda097b9000-7fda097ba000 rw-p 00026000 08:06 1577305 /lib/x86_64-linux-gnu/ld-2.23.so
7fda097ba000-7fda097bb000 rw-p 00000000 00:00 0
7ffd337fd000-7ffd3381e000 rw-p 00000000 00:00 0 [stack]
7ffd3391f000-7ffd33921000 r--p 00000000 00:00 0 [vvar]
7ffd33921000-7ffd33923000 r-xp 00000000 00:00 0 [vdso]
ffffffffff600000-ffffffffff601000 r-xp 00000000 00:00 0 [vsyscall]
Aborted (core dumped)

#> sudo mdadm --verbose --create /dev/md1 --level=mirror --raid-devices=2 --size=2790G --metadata=1.2 --name=startech-usb-enclosure-4bay-v2 /dev/sdd /dev/sdemdadm: automatically enabling write-intent bitmap on large array
mdadm: array /dev/md1 started.