This bugzilla has Keywords: Regression.  

Since no regressions are allowed between releases, 
it is also being proposed as a blocker for this release.  

Please resolve ASAP.

because has no such hardware: Server has internal 1-TB array on 3w_xxxx
controller (/dev/sdb), and large (> 1-TB)external fibre-channel array on an LSI
fibre-channel controller, so verified by code review.

There's no need for any special hardware - see Milan's reproducer in comment #13
of bug 179201:

Simple reproducible only with dmsetup - maybe need some change, depends on
memory conditions:

dmsetup create m1 --table "0 100000000 zero"
dmsetup create m2 --table "0 100000000 zero"
dmsetup create fm <<EOF
0 10000000 zero
10000000 33333333 mirror core 2 1024 nosync 2 /dev/mapper/m1 0 /dev/mapper/m2 0
EOF

dd if=/dev/zero of=/dev/mapper/fm seek=43333000

An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on the solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.

http://rhn.redhat.com/errata/RHBA-2008-0127.html