2.4.21-pre5-ac2: kernel oops with "swapoff -a"

[walt]

Hi Alan,

When I do "swapoff -a" I still see the kernel oops that began with -pre4-ac7
and has propagated to every 'ac' kernel since then.

It's a "null-pointer dereference" oops which does not crash the system --
I still don't understand how that is possible.

Am I really the only person having this problem?  The oops is 100% reproducible
so it's hard to believe no one else is seeing it.  It happens on all three of
the machines I try it on, so it doesn't seem to be hardware-specific.

Plain 2.4.21-pre5 does NOT show this problem, so it seems to be a patch that
was specifically introduced in -pre4-ac7 and I don't know enough to narrow
it any further than that.  I'm not an accomplished kernel debugger so I
can't offer much more info than that, but I'd like to help if you can give
me some hints what kind of information you might need to find the problem.