Re: Segfault loading draw.lisp (GCL b ackend) — draw2d/draw3d/gr2d unusable on Debian/Ubunt u-packaged Maxima 5.49.0

Hello,

On 20/08/2026 18:33, Leo Butler wrote:
> Hi,
> 
> I have encountered similar problems with the debian maxima packages in
> the last year. There are *several* possible causes. One which has not
> been mentioned is that the maxima-share package requires build-essential
> (Gcl uses the Gnu C compiler to compile things like `draw'). I just
> checked on my debian testing installation and neither the maxima nor
> maxima-share packages declare this as a dependency (try "apt-cache show
> maxima" as a super-user or with sudo).

Indeed. I filled a reportbug about this a few days ago:
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1143473

> 
> If you enter the following from the maxima command-line, it can give
> more information about the specific cause in your case:
> 
> :lisp (load #p"/usr/share/maxima/5.49.0/share/draw/draw.lisp")
> 
> The colon (:) must be the first character on the command line.
> 
> Good luck,
> Leo

Cheers,
Jerome

> 
> On Tue, Aug 18 2026, Jean-Michel Sarlat <[email protected]> wrote:
> 
>> Hello,
>>
>>    I'm hitting a reproducible segfault when loading the draw package on the
>> Debian/Ubuntu-packaged Maxima 5.49.0 (GCL backend). draw2d, draw3d, draw(),
>> and gr2d/gr3d are all
>>    unusable as a result, since they all trigger load(draw).
>>
>>    Environment:
>>    - Ubuntu 26.04 LTS (Resolute Raccoon), x86_64
>>    - Package: maxima 5.49.0+dsfg-2 (Debian/Ubuntu, maxima-share extra code)
>>    - Lisp: GCL 2.7.1 (git tag Version_2_7_2pre7),
>> /usr/lib/maxima/5.49.0/binary-gcl/maxima
>>
>>    Steps to reproduce:
>>    $ maxima --batch-string='load(draw)$'
>>
>>    Observed:
>>    loadfile: failed to load /usr/share/maxima/5.49.0/share/draw/draw.lisp
>>     -- an error. To debug this try: debugmode(true);
>>    Segmentation violation: c stack ok:signalling error
>>
>>    With debugmode(true), GCL's own signal handler catches the segfault and
>> turns it into a catchable error rather than killing the process — but draw
>> never actually finishes
>>    loading, so draw2d/draw3d/draw()/gr2d remain undefined afterwards.
>>
>>    What I've checked:
>>    - ulimit -s unlimited before starting maxima has no effect — this rules
>> out the OS thread stack; it looks like GCL's own fixed-size internal
>> control stack, baked into the
>>    saved core image.
>>    - Clearing ~/.maxima/binary and letting everything recompile from scratch
>> doesn't help either.
>>    - The Debian/Ubuntu maxima-share package ships only the .lisp sources for
>> the draw module (draw.lisp and its dependents: gnuplot.lisp, picture.lisp,
>> vtk.lisp,
>>    draw-index.lisp, wbd.lisp) — no precompiled .fasl/.o. So GCL has to
>> compile it from scratch on every load(draw), which seems to be exactly what
>> triggers the crash — my
>>    guess is the compiler overflows its C stack on this particular file,
>> given its size/macro complexity.
>>    - As a sanity check, I tried the maxima-sage package instead (Maxima
>> 5.45.1, but built against ECL rather than GCL). Same source, no crash:
>> load(draw), draw2d, draw3d, and
>>    draw(scene1, scene2) with gr2d scenes all work fine there, once I
>> installed libecl-dev, libgc-dev, libatomic-ops-dev and libffi-dev (needed
>> for ECL's own on-the-fly C
>>    compilation step). That strongly points to this being a GCL-specific
>> limitation rather than a bug in draw.lisp itself.
>>
>>    Has this been reported before, and is there a known workaround short of
>> switching Lisp backends — e.g. a way to raise GCL's control stack size for
>> the saved Maxima image,
>>    or a precompiled draw.fas that could be shipped with the package?
>>
>>    Thanks,
>>    Jean-Michel Sarlat
>>
>> _______________________________________________
>> Maxima-discuss mailing list
>> [email protected]
>> https://lists.sourceforge.net/lists/listinfo/maxima-discuss
>>
> 



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