kern/132068: [zfs] page fault when using ZFS over NFS on 7.1-RELEASE/amd64

[Edward Fisk]

I tried with the patch kindly provided by Jaakko.  The machine would no longer panic, but would instead deadlock every 1-2 hours when in use.  I then did a source upgrade to 8-CURRENT (27022008) with a GENERIC kernel, which had the same result: a deadlock every 1 to 2 hours when in use.

The machine is now running a GENERIC kernel with the following options added:

options INVARIANTS
options INVARIANT_SUPPORT
options WITNESS
options DEBUG_LOCKS
options DEBUG_VFS_LOCKS
options DIAGNOSTIC

Unfortunately, I've yet to be able to get it to deadlock, despite the workload on the machine not having changed.