Hi Thomas had some hotplug stress funnies and these appear to cure things. Should go into this merge window thingy, except the last one, which is fine for later.
The first is an obvious regression and has a Fixes line, the second looks like a pre-existing hole, but might be made easier to hit, although I can't readily tell you how. And while I could readily hit the first hole, I didn't manage to trigger the second, but Thomas had enough trace data to confirm he could.
