Re: backward compatibility: how far can it reasonably go?

[Paul Goyette <paul%whooppee.com@localhost>]

On Tue, 7 Dec 2021, Greg A. Woods wrote:

> So I've got a couple of old but important machines (Xen amd64 domUs)
> running NetBSD-5, and I've finally decided that I'm reasonably well
> enough prepared to try upgrading them.
>
> However it seems a "modern" (9.99.81, -current from about 2021-03-10)
> kernel with COMPAT_40 isn't able to run some of the userland on those
> systems.
>
> Is this something that should work?

I believe that this should work.

> If it should I think it would make the upgrade much easier as I could
> then plop down the new userland and run etcupdate.  (there are of course
> alternative ways to do the upgrade, eased by the fact they are domUs (*))
>
> The most immediate problems I noticed are with networking.  ifconfig -a
> returns without printing anything, and trying to enable IPF crashes:

Without looking at the details of your backtrace, the issue with
ifconfig(8) could be related to PRs kern/54150 and/or kern/54151.



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