> So, I added DDB_* to my sparc/MP config and this is the dmesg and
> stack when we hit the panic in lockmgr.

This is a known issue with MP kernels on hypersparc machines. Here's a
previous message on the subject:

>> I get the same thing on a SS10 with a dual Ross 100 MHZ module.  It didn't
>> happen, however, when I had two TMS390Z50 in the machine.
>>
>> I presumed that something is not quite ready.
>
>True. MP hypersparc machines all do this. The problem is in the smp
>version of the cache flush routines: pages must remain mapped in the
>MMU until the page cache flushes are done on all CPUs. Currently,
>the primary CPU races ahead and unmaps a page before the other CPUs
>get around to flushing it from their caches.
>
>At least that's my current conjecture on this issue.
>