Re: texinfo-7.2.92 pretest available [segfault building gcc docs]

On Tue, Feb 24, 2026 at 12:10:56AM +0100, Hilmar Preusse wrote:
> On 17.02.26 Gavin Smith ([email protected]) wrote:
> 
> Hello,
> 
> > The next pretest distribution for the next Texinfo release has been
> > uploaded to
> > 
> > https://alpha.gnu.org/gnu/texinfo/texinfo-7.2.92.tar.xz
> > 
> > Many thanks to all those who have tested earlier pretests and reported
> > the results.  There have not been many changes since the previous pretest,
> > and we hope to release this as Texinfo 7.3 in a few days' time.
> > 
> 
> We packaged the pre-releases in Debian and did some tests build of
> Debian packages using the pretest version to figure, if the new
> version breaks things in the Debian archive.  We found that the
> gcc-12-doc_12.2.0-1 fails to build:
> 
> gcc/ada/gnat_ugn.texi:24453: warning: @emph should not appear in @code
> gcc/ada/gnat_ugn.texi:24473: warning: @emph should not appear in @code
> gcc/ada/gnat_ugn.texi:28375: warning: @emph should not appear in @code
> Segmentation fault (core dumped)
> make[2]: *** [debian/Makefile:116: gnat_ugn.html] Error 139

Thanks for running these tests and reporting this.  We definitely don't
want to be releasing a program that segfaults on input, especially on
gcc documentation.

I've been able to reproduce the segmentation fault.  I tried building
gnat_ugn.texi after downloading manual sources from
https://gcc.gnu.org/onlinedocs/12.2.0/.

I had to use the full command line from your coredumpctl output below,
with the addition of a --force option to account for a missing input file:

perl ../../tta/perl/texi2any.pl -D $'fncpp cpp' -D $'fncppint cppinternals' -D $'fngcc gcc' -D $'fngxx g++' -D $'fngccint gccint' -D $'fngccinstall gccinstall' -D $'fngfortran gfortran' -D $'fntreelang treelang' -D $'fngnatrm gnat_rm' -D $'fngnatrmlong GNAT Reference Manual' -D $'fngnatugn gnat_ugn' -D $'fngnatugnlong GNAT User\'s Guide' -D $'fngnatstyle gnat-style' -D $'fngccgo gccgo' -D $'fngcov gcov' -D $'fngcovtool gcov-tool' -D $'fngcovdump gcov-dump' -D $'fnlibgomp libgomp' -D $'fnlibitm libitm' -D $'fnlibquadmath libquadmath' -D $'fnltodump lto-dump' -D $'BUGURL http://bugs.debian.org/' --no-split -Igcc/doc -Igcc/doc/include --html -o gnat_ugn.html gcc/ada/gnat_ugn.texi --force

Valgrind reports an error:

==2562765== Memcheck, a memory error detector
==2562765== Copyright (C) 2002-2022, and GNU GPL'd, by Julian Seward et al.
==2562765== Using Valgrind-3.22.0 and LibVEX; rerun with -h for copyright info
==2562765== Command: perl ../../tta/perl/texi2any.pl -D fncpp\ cpp -D fncppint\ cppinternals -D fngcc\ gcc -D fngxx\ g++ -D fngccint\ gccint -D fngccinstall\ gccinstall -D fngfortran\ gfortran -D fntreelang\ treelang -D fngnatrm\ gnat_rm -D fngnatrmlong\ GNAT\ Reference\ Manual -D fngnatugn\ gnat_ugn -D fngnatugnlong\ GNAT\ User's\ Guide -D fngnatstyle\ gnat-style -D fngccgo\ gccgo -D fngcov\ gcov -D fngcovtool\ gcov-tool -D fngcovdump\ gcov-dump -D fnlibgomp\ libgomp -D fnlibitm\ libitm -D fnlibquadmath\ libquadmath -D fnltodump\ lto-dump -D BUGURL\ http://bugs.debian.org/ --no-split -Igcc/doc -Igcc/doc/include --html -o gnat_ugn.html gcc/ada/gnat_ugn.texi --force
==2562765== Parent PID: 2440939
==2562765== 
==2562765== Invalid read of size 1
==2562765==    at 0x484F286: __strlen_sse2 (in /usr/libexec/valgrind/vgpreload_memcheck-amd64-linux.so)
==2562765==    by 0x6A3E5E5: text_append (in /home/g/src/texinfo/GIT/tta/C/.libs/libtexinfo.so.1.0.0)
==2562765==    by 0x6A51259: convert_to_normalized_internal (in /home/g/src/texinfo/GIT/tta/C/.libs/libtexinfo.so.1.0.0)
==2562765==    by 0x6A51572: convert_to_normalized_internal (in /home/g/src/texinfo/GIT/tta/C/.libs/libtexinfo.so.1.0.0)
==2562765==    by 0x6A51618: convert_to_normalized (in /home/g/src/texinfo/GIT/tta/C/.libs/libtexinfo.so.1.0.0)
==2562765==    by 0x6A51AD1: convert_to_identifier (in /home/g/src/texinfo/GIT/tta/C/.libs/libtexinfo.so.1.0.0)
==2562765==    by 0x6A51B65: convert_contents_to_identifier (in /home/g/src/texinfo/GIT/tta/C/.libs/libtexinfo.so.1.0.0)
==2562765==    by 0x6B9B8D2: normalized_sectioning_command_filename (in /home/g/src/texinfo/GIT/tta/C/.libs/libtexinfo-convert.so.1.0.0)
==2562765==    by 0x6BDB7CE: new_sectioning_command_target (in /home/g/src/texinfo/GIT/tta/C/.libs/libtexinfo-convert.so.1.0.0)
==2562765==    by 0x6BDBEF2: set_root_commands_targets_node_files (in /home/g/src/texinfo/GIT/tta/C/.libs/libtexinfo-convert.so.1.0.0)
==2562765==    by 0x6BDCD32: html_prepare_conversion_units_targets (in /home/g/src/texinfo/GIT/tta/C/.libs/libtexinfo-convert.so.1.0.0)
==2562765==    by 0x753F48A: XS_Texinfo__Convert__ConvertXS_html_output (in /home/g/src/texinfo/GIT/tta/perl/XSTexinfo/.libs/ConvertXS.so)
==2562765==  Address 0x255025502550255 is not stack'd, malloc'd or (recently) free'd
==2562765== 


I'm hopeful we can investigate and fix this.

With fewer options, there is not a segfault, but still outputs a large number
of warnings about nesting which I do not believe are correct:

$ perl ../texinfo-7.2.92/tta/perl/texi2any.pl -I gcc/gcc/doc/include/ gcc/gcc/ada/gnat_ugn.texi
gcc/gcc/ada/gnat_ugn.texi:18: warning: @definfoenclose is obsolete
gcc/gcc/ada/gnat_ugn.texi:19: warning: @definfoenclose is obsolete
gcc/gcc/doc/include/gcc-common.texi:11: @include: could not find gcc-vers.texi
gcc/gcc/ada/gnat_ugn.texi:55: warning: undefined flag: version-GCC
gcc/gcc/ada/gnat_ugn.texi:942: warning: @emph should not appear in @item
gcc/gcc/ada/gnat_ugn.texi:946: warning: @emph should not appear in @item
gcc/gcc/ada/gnat_ugn.texi:950: warning: @emph should not appear in @item
gcc/gcc/ada/gnat_ugn.texi:1237: warning: @emph should not appear in @item
gcc/gcc/ada/gnat_ugn.texi:1250: warning: @emph should not appear in @item
gcc/gcc/ada/gnat_ugn.texi:1263: warning: @emph should not appear in @item
gcc/gcc/ada/gnat_ugn.texi:1276: warning: @emph should not appear in @item
gcc/gcc/ada/gnat_ugn.texi:1289: warning: @emph should not appear in @item
gcc/gcc/ada/gnat_ugn.texi:1300: warning: @emph should not appear in @item
gcc/gcc/ada/gnat_ugn.texi:1314: warning: @emph should not appear in @item
gcc/gcc/ada/gnat_ugn.texi:1321: warning: @emph should not appear in @item
gcc/gcc/ada/gnat_ugn.texi:1329: warning: @emph should not appear in @item
gcc/gcc/ada/gnat_ugn.texi:1352: warning: @emph should not appear in @item
gcc/gcc/ada/gnat_ugn.texi:1367: warning: @emph should not appear in @item
gcc/gcc/ada/gnat_ugn.texi:1378: warning: @emph should not appear in @item
gcc/gcc/ada/gnat_ugn.texi:1390: warning: @emph should not appear in @item
gcc/gcc/ada/gnat_ugn.texi:1401: warning: @emph should not appear in @item
gcc/gcc/ada/gnat_ugn.texi:1422: warning: @emph should not appear in @item
gcc/gcc/ada/gnat_ugn.texi:1463: warning: @emph should not appear in @item

- and it continues.

gcc-vers.texi is not present anywhere in docs-sources.tar.gz that I downloaded
and is presumably responsible for setting the version-GCC flag.

There's nothing wrong with @emph in @item, AFAIK.

When building after configuring with --disable-perl-xs, the error messages
do not occur:

$ perl ../tta/perl/texi2any.pl -I gcc/gcc/doc/include/ gcc/gcc/ada/gnat_ugn.texi
gcc/gcc/ada/gnat_ugn.texi:18: warning: @definfoenclose is obsolete
gcc/gcc/ada/gnat_ugn.texi:19: warning: @definfoenclose is obsolete
gcc/gcc/doc/include//gcc-common.texi:11: @include: could not find gcc-vers.texi
gcc/gcc/ada/gnat_ugn.texi:55: warning: undefined flag: version-GCC

So there is also a bug here that the warnings are not consistent
between XS/pure Perl code, and appear to be incorrect with the XS code.


> the coredumpctl reports:
> 
> root@rasppi3:~# coredumpctl info /run/schroot/mount/arm64-sid-a3802f59-def6-43d6-bfe8-43b535c91509/usr/bin/perl
>            PID: 620253 (makeinfo)
>            UID: 1000 (hille)
>            GID: 1000 (hille)
>         Signal: 11 (SEGV)
>      Timestamp: Mon 2026-02-23 20:14:21 CET (3h 42min ago)
>    Command Line: /usr/bin/perl /usr/bin/makeinfo -D $'fncpp cpp' -D $'fncppint cppinternals' -D $'fngcc gcc' -D $'fngxx g++' -D $'fngccint gccint' -D $'fngccinstall gccinstall' -D $'fngfortran gfortran' -D $'fntreelang treelang' -D $'fngnatrm gnat_rm' -D $'fngnatrmlong GNAT Reference Manual' -D $'fngnatugn gnat_ugn' -D $'fngnatugnlong GNAT User\'s Guide' -D $'fngnatstyle gnat-style' -D $'fngccgo gccgo' -D $'fngcov gcov' -D $'fngcovtool gcov-tool' -D $'fngcovdump gcov-dump' -D $'fnlibgomp libgomp' -D $'fnlibitm libitm' -D $'fnlibquadmath libquadmath' -D $'fnltodump lto-dump' -D $'BUGURL http://bugs.debian.org/' --no-split -Igcc/doc -Igcc/doc/include --html -o gnat_ugn.html gcc/ada/gnat_ugn.texi
>     Executable: /run/schroot/mount/arm64-sid-a3802f59-def6-43d6-bfe8-43b535c91509/usr/bin/perl
> 
> So it is basically the perl compiler, which crashes when executing
> makeinfo. However due to the XS extensions it may be C code from
> TeXInfo too. I'll try to generate backtraces to figure if TeXInfo
> causes the issue.

It's almost certainly a bug in the XS extensions, rather than a segfault
in the Perl interpreter itself.

> 
> I don't see that as showstopper anyway. Keep me in Cc, I'm not
> subscribed.
> 
> Hilmar