[nullfs] [panic] null with unref'ed lowervp

[Martin Schütte]

Gleb Kurtsou wrote:
> In my understanding null_checkvp assumptions doesn't hold in null_lock
> and null_unlock. So I'd suggest you running without DIAGNOSTIC or try
> attached patch instead.

Thanks.
I installed the patch now.

Because I already reduced the number of nullmounts I cannot really
'test' it but I will write in case I see the issue again.

-- 
Martin