Bug#568922: mdadm: data-check of RAID array md0 results in soft lockup of CPU's

[Tim Small]

What happens if you disable NCQ?  Seen similar crap on another system
with WD drives, and I suspect a firmware bug.

That system was OK with a queue depth of 2 or less.  You can confirm
this with hdparm -t, I think.

This problem should really be assigned to the kernel I suppose, as all
that mdadm does is to tell the kernel to execute the check....

Ta,

Tim.