Dear maintainer:

During a rebuild of all packages in trixie (after the 13.6 point release),
several packages using sphinx FTBFS in this way:
------------------------------------
writing output...
building [html]: targets for 507 source files that are out of date
updating environment: [new config] 507 added, 0 changed, 0 removed

Exception occurred:
   File "/usr/lib/python3.13/multiprocessing/connection.py", line 399, in _recv
     raise EOFError
EOFError
------------------------------------

The above example is for python3.13 and a full log is available here:

https://tests.reproducible-builds.org/debian/rbuild/trixie/amd64/python3.13_3.13.5-2+deb13u3.rbuild.log.gz

I'm using the affects line for all known affected packages.

Note: Please keep the bug open until it's fixed in stable (using the
changelog in an upload for trixie is of course ok). I've marked the bug
as fixed in forky/sid because I can't reproduce the issue in forky/sid,
so the bug should not affect sphinx in forky/sid.

If required I can offer a VM to reproduce.

Thanks.

affects 1142056 src:buildbot src:wireplumber
thanks

The above two packages are also affected, but they only fail to build
randomly here (as opposed to "always" in the other cases).

Additionally, the following packages make sphinx to segfault randomly,
resulting in a build failure:

src:aiodukeenergy
src:flask-debugtoolbar
src:python-term-image

Not sure if that's related to the present bug or not.

Thanks.

Hello,

Bug #1142056 in sphinx reported by you has been fixed in the
Git repository and is awaiting an upload. You can see the commit
message below and you can check the diff of the fix at:

https://salsa.debian.org/python-team/packages/sphinx/-/commit/947ec0ef83f8b8018daca3f6a277fa7c134e8c87
------------------------------------------------------------------------
Add a patch to fix EOFError with parallel builds.

Closes: #1142056.
------------------------------------------------------------------------

(this message was generated automatically)
-- 
Greetings

https://bugs.debian.org/1142056

Hi Santiago!
https://salsa.debian.org/python-team/packages/sphinx/-/commits/debian/trixie?ref_type=heads

Some pipeline jobs failed, because python3.13 interpreter segfaults. This is
a different issue, and it looks more like a bug in python3.13, not in sphinx.
It may be the same issue as #1142107 (also python3.13, also segfault, also
Trixie).

I cannot reproduce it in my Trixie chroot (I have just built sphinx without
issues 3 times in a row). If you have this segfault in your VM, maybe you can
obtain a C stack trace with gdb? Pybuild prints the command it runs, so you
just need to replace "python3.13" with "gdb --args python3.13":

I: pybuild base:311: cd /build/package/package/.pybuild/cpython3_3.13/build; python3.13 -m pytest --verbose --ignore tests/test_writers/test_api_translator.py

My hypothesis is that it broke between python3.13 3.13.5-2+deb13u2 and
3.13.5-2+deb13u3, so if you can test with 3.13.5-2+deb13u2, that would also
help. Or give me access and I will test when I have time, if you like that
option more.

I agree, this looks like a bug in src:python3.13.

I'll give you a VM where python segfaults 50% of the time while trying
to build sphinx in trixie (see private email).

Thanks.

Ok, I created binary packages from that, put them in a private repo,
and then, using the modified sphinx packages, tried to build the
following affected packages, which have a not too long build-time:

kitty
groonga
openmpi
flint
blender-doc

They still fail using the modified sphinx packages. Sample build log
here, for openmpi:

https://people.debian.org/~sanvila/build-logs/trixie/

So I guess it is something else.

Thanks.

Hi. This is probably the python3.13 bug:

https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1141977

and at this point I really wonder if there was a bug in sphinx at all
(in which case we would not need an upload for trixie at all).

I leave the reassign to you if you believe it's appropriate.

Thanks.

Hi!

Thank you! I did not see this bug when searching, for some reason.
EOFError: it appeared recently so it may be related to python3.13 update, but
it may still be a bug in Sphinx.

(I still did not have time to look deeper, sorry.)

Control: notfixed -1 sphinx/9.1.0-4
Control: reassign -1 python3.13 3.13.5-2+deb13u3
Control: tags -1 - pending
Control: tags 1141977 + trixie
Control: affects -1 - src:python3.13
Control: affects 1141977 src:blender-doc src:cp2k src:flint src:groonga src:kitty src:openmpi
Control: merge 1141977 -1

Actually I have just tried to build openmpi on your second VM, and I see in
dmesg output that we have a segfault here too.

[  516.735856] sphinx-build[247755]: segfault at 1 ip 00000000005739c3 sp 00007ffeca2084c0 error 4 in python3.13[1739c3,420000+31f000] likely on CPU 1 (core 1, socket 0)
[  516.742635] Code: 00 00 00 00 00 66 66 2e 0f 1f 84 00 00 00 00 00 66 66 2e 0f 1f 84 00 00 00 00 00 66 66 2e 0f 1f 84 00 00 00 00 00 90 48 89 f1 <48> 8b 3e 48 8b 51 10 48 8b 41 08 48 89 fe 85 d2 0f 88 c2 6d ec ff
[ 2630.616676] systemd-ssh-generator[248529]: Failed to query local AF_VSOCK CID: Cannot assign requested address
[85928.309361] sphinx-build[495026]: segfault at ffffffffffffffff ip 000000000059a56a sp 00007ffc6d59b4e0 error 5 in python3.13[19a56a,420000+31f000] likely on CPU 0 (core 0, socket 0)
[85928.314974] Code: 01 00 00 0f 87 b5 01 00 00 8d 75 ff c1 ee 04 8d 04 36 49 8b 04 c7 48 8b 78 10 48 39 f8 0f 84 1f 02 00 00 48 8b 58 08 83 00 01 <48> 8b 0b 48 89 48 08 48 85 c9 0f 84 f4 00 00 00 8b 82 10 1d 00 00

The child process segfaults, and then the main process prints a traceback
with EOFError because it could not receive anything from the child process.

So this is most probably the same issue as #1141977, so I am merging them.

I have run `init 0` on both VMs now, thanks again for providing them.

We believe that the bug you reported is fixed in the latest version of
python3.13, which is due to be installed in the Debian FTP archive.

A summary of the changes between this version and the previous one is
attached.

Thank you for reporting the bug, which will now be closed.  If you
have further comments please address them to 1141977@bugs.debian.org,
and the maintainer will reopen the bug report if appropriate.

Debian distribution maintenance software
pp.
Stefano Rivera <stefanor@debian.org> (supplier of updated python3.13 package)

(This message was generated automatically at their request; if you
believe that there is a problem with it please contact the archive
administrators by mailing ftpmaster@ftp-master.debian.org)
Format: 1.8
Date: Wed, 15 Jul 2026 17:25:40 -0300
Source: python3.13
Architecture: source
Version: 3.13.5-2+deb13u4
Distribution: trixie
Urgency: medium
Maintainer: Matthias Klose <doko@debian.org>
Changed-By: Stefano Rivera <stefanor@debian.org>
Closes: 1141977
Changes:
 python3.13 (3.13.5-2+deb13u4) trixie; urgency=medium
 .
   * Patch: Fix use-after-free in dict.clear() with embedded values.
     Resolves a regression in 3.13.5-2+deb13u3. (Closes: #1141977)
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