There seemed to be increase in Athlon users reporting MCEs in 2.6 that
they never saw in 2.4 and I didn't buy the "2.6 pushes hardware harder"
for a second given folks are running 2.4+preempt+O(1) etc patchkits
without problems.

So I did a mini-audit of the mcheck code.

How embarressing. Another fix that went into 2.4 that never made
it forward. Once I'm done with various Red Hat administrivia
I'll see if I can devote some time to going through the changesets
mailing list. I wonder just how many other really stupid bugs
like this got fixed and not brought forward.