bhyve: assertion in pci_vtblk_proc

[Peter Grehan]

Hi Andriy,

> While running some fs-related workloads in a Gentoo guest bhyve crashed with the
> following assertion:
>
> Assertion failed: (n >= 2 && n <= BLOCKIF_IOV_MAX + 2), function pci_vtblk_proc,
> file /usr/src/usr.sbin/bhyve/pci_virtio_block.c
  ...
> Please let me know if you would like more details.

  Would you be able to get the value of 'n' from gdb ?

  This is possibly a similar issue to that seen under Windows, which I 
had an attempt at fixing with r282922 (subsequently reverted).

later,

Peter.