ZFS-NFS kernel panic under load

[Rick Macklem]

On Wed, 27 Aug 2008, Weldon S Godfrey 3 wrote:

>
> Well, I am not sure if it was exactly that bug, since the last time I 
> paniced, it never dumped to memory.  Although this time i paniced, it started 
> to dump then locked up solid.
>
> before I paniced I did get an error message at the end of the panic:
>
>
> Stopped at nfsrv_access at 0x190 testb 0x1, 0xa4 (%rax)
>
Well, I'd guess that is the following source line:
 		if (rdonly || (vp->v_mount->mnt_flag & MNT_RDONLY)) {
since "mnt_flag" is way down in the structure and MNT_RDONLY == 0x1.

This suggests that v_mount is no longer valid, but I have no idea why that
might happen. (This was looking at the -current nfsserver sources, but I
don't think they've changed much.

Maybe someone who knows ZFS and how it handles the mount structure might
have some idea?

rick