Date: Tue, 31 Mar 2020 15:55:34 -0600 From: Warner Losh <imp@bsdimp.com> To: Ed Maste <emaste@freebsd.org> Cc: freebsd-reproducibility@freebsd.org Subject: Re: Nonreproducible kernel modules on stable/12 Message-ID: <CANCZdfoHt6tm5D3w_QgtQozToutr_UAipOL4iS6Ef5Q%2BTebDjQ@mail.gmail.com> In-Reply-To: <CAPyFy2Bzuk3tyrPdkw4L2xD%2BWE6qG1mRDG0hGEx0QOxw%2BXVDvA@mail.gmail.com> References: <CAPyFy2Bzuk3tyrPdkw4L2xD%2BWE6qG1mRDG0hGEx0QOxw%2BXVDvA@mail.gmail.com>
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On Tue, Mar 31, 2020 at 8:08 AM Ed Maste <emaste@freebsd.org> wrote:
> Originally reported off-list, during a stable/12 freebsd-update build
> kernel modules are not reproducible and thus get included in the
> update.
>
> diffoscope reports that the .SUNW_ctf section is responsible:
>
> --- cam.0.ko
> +++ cam.1.ko
> ├── readelf --wide --sections {}
> ...
> │ [30] .shstrtab STRTAB 0000000000000000 0ea828
> 0001f8 00 0 0 1
> │ - [31] .SUNW_ctf PROGBITS 0000000000000000 0f29d8
> 00e2ad 00 32 0 4
> │ + [31] .SUNW_ctf PROGBITS 0000000000000000 0f29d8
> 00e2b1 00 32 0 4
> │ [32] .symtab SYMTAB 0000000000000000 0e12b8
> 009570 18 33 1001 8
> ...
> ├── readelf --wide --decompress --hex-dump=.SUNW_ctf {}
> │ @@ -1,3630 +1,3631 @@
> │
> │ Hex dump of section '.SUNW_ctf':
> │ 0x00000000 f1cf0201 00000000 00000000 00000000 ................
> │ 0x00000010 08000000 96040000 fc250000 f4310100 .........%...1..
> │ - 0x00000020 6aeb0000 78dabc7d 077c54c5 16f7ccbd j...x..}.|T.....
> │ - 0x00000030 774b42ca 26b48524 b0402001 02440d10 wKB.&..$.@ ..D..
> ...
> │ + 0x00000020 6feb0000 78dabc7d 077c54c5 16f7ccdc o...x..}.|T.....
> │ + 0x00000030 bb252165 13da4242 586a0204 081820d4 .%!e..BBXj.... .
>
> (And build-ID and GNU debuglink differ as a result.)
>
> Running ctfdump and comparing the result shows the issue:
>
> --- a 2020-03-31 10:04:39.766567000 -0400
> +++ b 2020-03-31 10:04:44.663292000 -0400
> @@ -11,11 +11,11 @@
> cth_funcoff = 1174
> cth_typeoff = 9724
> cth_stroff = 78324
> - cth_strlen = 60266
> + cth_strlen = 60271
>
> - Label Table
> ----------------------------------------------------------------
>
> - 2407 FreeBSD 12.1-STABLE amd64 1201512
> + 2407 FreeBSD 12.1-FUTUREBUILD amd64 1201512
>
So is this before/after the change? When I built stable/12 twice in a row,
I get identical binaries. I get the same md5's for all the .ko's build as
part of buildkernel/installkernel.
Why is this string even in the binary? The string FUTUREBUILD doesn't
appear at all in newvers.sh. Nor anywhere in the FreeBSD tree. This has got
to be a FreeBSD update builder bug. Where's the source to it? The bug is in
there.
Warner
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