starting >=2.6.36 FATAL: Setup length exceeds 31 maximum; kernel setup will overwrite boot loader

[Linda Walsh <lkml@tlinx.org>]

Fatal: Setup length exceeds 31 maximum; kernel setup will overwrite
boot loader

Starting with 2.6.36, I started getting the above message.

It didn't seem what options I pruned out of the kernel
ipv6 support, iptables support, any thing I could think of
that would be a 'large chunk of space', nothing would make
it "fit" the way 2.6.35 did.

I didn't turn on options from options from 2.6.35 -> 2.6.36,
but did turn on things like BIOS blk throttling which seemed
low cost.  I set the lower BIOS reserved amount to 4K, which
seemed to be the default under the old system (?), though
this system hasn't ever been tested w/standby or hibernate
so don't know if this is a correct setting, but is unlikely relevant.

So where did this extra length come from?

I *hoped* it was a fluke w/26.36, that would disappear in 26.37...but
nep.  In searching for causes I saw one message pointing to the
XEN subsystem, but I made sure to remove that on both setups and that
made no difference.

So what's caused the sudden bump and how do I get around it?