Re: kern/51148: i386 install floppies no longer boot

[Andreas Gustafsson <gson%gson.org@localhost>]

Maxime,

You wrote:
> First of all, I'm not subscribed to netbsd-bugs@, so please forward your mails
> to me.

Will do.  I would have mailed you about the initial report if you had
been the only developer to commit during the period of build breakage
when the problem appeared, but there were commits by four developers,
and no easy way for me to determine which of them was at fault.

> I have carefully investigated the mappings on amd64 and i386 with a kernel page
> explorer I wrote, and there no issue. The levels are all linear, with no holes
> in the middle, they are correctly linked, and they cover the whole kernel image,
> preloaded modules and bootstrap tables.
> 
> In fact, there appears to be one bug in the L1 slot that should normally point
> to the first page of the data segment: it seems to be destroyed. But this issue
> was already here before my changes, so I didn't introduce it.
> 
> The changes from me you mentioned are all trivial, and it seems highly unlikely
> to me that they cause the install failure. Normally, if there were a bug, it
> should have been in the previous commmits. Also, my changes are in no way
> install-related, and as far as I know, the mappings are the same on
> CD/USB/floppy/whatever.
> 
> My guess, right now, is that my alignment changes in kern.ldscript somehow
> trigger the aforementioned L1 slot bug on floppy installs.
> 
> I don't have a floppy device, and right now my NetBSD resources are limited.

If you can run misc/py-anita from pkgsrc against an i386 release
build, that should reproduce the problem without the need for a
physical floppy device or even a NetBSD host.

> The
> only thing I can do is asking.
> 
> 	Is the problem still present? (I don't see new entries in the log)

Yes, the problem is still present.  I'm not sure what you mean about
not seeing new entries; the newest test runs are from today, and still
failing with the same error:

  http://releng.netbsd.org/b5reports/i386/commits-2016.05.html#2016.05.25.10.15.01

> 	We are talking about GENERIC, and not GENERIC-PAE, right?

Yes.

> 	Does reverting only [1] fix the problem?

I will try that and report back.

> 	What if you put 'fillkpt' instead of 'fillkpt_nox' in [1]?

I will try that, too.

> Thanks.
> 
>   [1] 2016.05.15.07.17.53 maxv src/sys/arch/i386/i386/locore.S 1.124
-- 
Andreas Gustafsson, gson%gson.org@localhost