kernel refuses devices mdadm -E accepts

["Wesley W. Terpstra" <wesley@terpstra.ca>]

I have a raid5 array for which every disk, when examined with "mdadm
-E /dev/sd[abcd]4" shows a Version: 1.2 superblock with a valid
checksum.

However, when I try:
mdadm -A /dev/md/backing /dev/sd[abcd]4
mdadm says:
mdadm: failed to add /dev/sdc4 to /dev/md/backing: Invalid argument
mdadm: failed to add /dev/sdb4 to /dev/md/backing: Invalid argument
mdadm: failed to add /dev/sda4 to /dev/md/backing: Invalid argument
mdadm: failed to add /dev/sdd4 to /dev/md/backing: Invalid argument
mdadm: /dev/md/backing assembled from 0 drives - need all 4 to start
it (use --run to insist)
The kernel says:
md: sdc4 does not have a valid v1.2 superblock, not importing!
md: md_import_device returned -22
md: sdb4 does not have a valid v1.2 superblock, not importing!
md: md_import_device returned -22
md: sda4 does not have a valid v1.2 superblock, not importing!
md: md_import_device returned -22
md: sdd4 does not have a valid v1.2 superblock, not importing!
md: md_import_device returned -22

I was in the middle of a reshape of this 4-disk raid5 when something
rebooted the computer. The system seems otherwise fine, and I suspect
someone in the house.

What is the correct next step? Should I try --run ? I would obviously
prefer not to lose the data on this array. I expect that the reshape
was NOT complete, so just recreating the array will probably corrupt
its contents.

Kernel version 3.17.8 and mdadm version 3.3.2.

Thanks for any help. If I lose this array, I am going to face a lot of grief...