Re: Serious compatibility breakage in -current.

On Dec 1, 2007 9:48 PM, Kostik Belousov <kostikbel_at_gmail.com> wrote:
> Is this some new code ? I did tested it on CLUCL-19d compiled for
> RELENG_6. Also, the sigbus_handler() from lisp/FreeBSD-os.c rev 1.12
> does not contain the check, it seems (that describes why it worked for
> me).

Okay, this clearly explains why we are seeing different things.  The
si_code check was added in version 1.16.  This postdates the release
of CMUCL your first patch was tested against.  Incidentally, I added
that check to the SIGBUS handler and should have known that it does
not appear in a formal release.  Sorry about that.

> Could you, please, describe what was tested in more details ? Did
> you run the CMUCL (and sbcl) with the patch ? If yes, could you, please,
> show the file(1) output on the bin/lisp and bin/sbcl binary ?

I have a small test program that maps a page with PROT_NONE and
generates a protection violation by writing a byte to it.  The "mmap6"
executable was compiled on a FreeBSD 6.1 system.  The "mmap7"
executable was compiled on my 7.0-BETA3 system with your patch
applied.  Below is a transcript of these two programs being run on the
patched 7.0-BETA3 system.

freebsd7% file mmap6
mmap6: ELF 32-bit LSB executable, Intel 80386, version 1 (FreeBSD),
dynamically linked (uses shared libs), not stripped
freebsd7% ./mmap6
__FreeBSD_version=601000
signum=10,info->si_code=12,context=0xbfbfe9d0
freebsd7% file ./mmap7
./mmap7: ELF 32-bit LSB executable, Intel 80386, version 1 (FreeBSD),
for FreeBSD 7.0 (700055), dynamically linked (uses shared libs),
FreeBSD-style, not stripped
freebsd7% ./mmap7
__FreeBSD_version=700055
signum=11,info->si_code=2,context=0xbfbfe9e0

The source code to this program is in a bug report I submitted a few
days ago and errantly filed under "misc".  Please visit
http://www.freebsd.org/cgi/query-pr.cgi?pr=118304 and page down to the
"How-To-Repeat" heading.

I have also recompiled CMUCL on a FreeBSD 7 system starting with a
FreeBSD 6 binary and everything seems to work.  I believe the output
of my small test program provides sufficient proof that the interfaces
we rely on are working as expected.