Re: FreeBSD build regressions

From: Warner Losh <imp@bsdimp.com>
To: Peter Maydell <peter.maydell@linaro.org>
Cc: "Alex Bennée" <alex.bennee@linaro.org>,
	"Ed Maste" <emaste@freebsd.org>,
	"QEMU Developers" <qemu-devel@nongnu.org>,
	"Gerd Hoffmann" <gerd@kraxel.org>,
	"Li-Wen Hsu" <lwhsu@freebsd.org>
Subject: Re: FreeBSD build regressions
Date: Fri, 19 Feb 2021 11:28:42 -0700	[thread overview]
Message-ID: <CANCZdfpcDhWt0fh3kvM_+RfEaggkeWFTKJLy0CSofstFjOQkbg@mail.gmail.com> (raw)
In-Reply-To: <CAFEAcA9hW-hvjrS+tFt9KAkvVH+cCS_4JkMx+TUNEy5uFU-qaw@mail.gmail.com>

[-- Attachment #1: Type: text/plain, Size: 2039 bytes --]

On Fri, Feb 19, 2021 at 9:14 AM Peter Maydell <peter.maydell@linaro.org>
wrote:

> On Fri, 19 Feb 2021 at 16:08, Warner Losh <imp@bsdimp.com> wrote:
> > FreeBSD builds packages on the oldest supported version in the stable
> branch. Due to forward compatibility, that means all supported versions of
> FreeBSD 12.x will work. Recently, FreeBSD 12.1 became unsupported, so the
> build machines clicked forward to 12.2. Since there's no 'forward
> compatibility' guarantees, this problem was hit. While you can run binaries
> compiled on old versions of the software on new versions of the system, you
> can't necessarily do the inverse because new symbols are introduced (in
> this case close_range).
>
> It makes perfect sense that you don't want to support older
> versions forever and that at some point newer packages aren't
> valid on old systems, but I don't understand why an
> older 12.1 system then says "but I'm going to go ahead and
> install these won't-work packages anyway" rather than
> "oh dear, I'm out of support, there are no newer packages
> available, I will install whatever the last archived version
> of the package for my OS version is" (or "I will install nothing").
> I'm surprised this doesn't break a lot of real-world users...
>

That's a reasonable expectation. I'd kinda expected that to be the default,
but it looks like it might not be. I'll see if I can get the freebsd vm
updated to use something safer and/or work with the pkg folks to get it to
do the safe thing here if there's no easy way to do this with command line
/ config settings. I think the issue is that we set IGNORE_OSVERSION which
is needed for the case when we were running 12.0 packages on 12.1, but it's
harmful for this case. This highlights, I think, a rough edge in pkg.

Short term, I'll bump things up to 12.2 which will take care of the
immediate issue. I should have a patch by later in the day.... I may also
have a patch to detect the mismatch directly and report it until this issue
can be resolved in FreeBSD's pkg.

Warner

[-- Attachment #2: Type: text/html, Size: 2608 bytes --]