Hi All,
I have recently released Octave 5.1.0

https://cygwin.com/ml/cygwin-announce/2020-01/msg00010.html
https://cygwin.com/ml/cygwin-announce/2020-01/msg00011.html

that I built and packaged around 28 of December without
any compilation and test issue.

Than I passed to build the next version and started to see
unexpected segfault during the package test.
Trying to investigate I rebuilt the 5.1.0 and now I see also
there the same thing:

   libinterp/corefcn/file-io.cc-tst 
...............................fatal: caught signal Segmentation fault 
-- stopping myself...
/bin/sh: line 1:  3771 Segmentation fault      (core dumped) /bin/sh 
../run-octave --norc --silent --no-history -p 
/cygdrive/d/cyg_pub/devel/octave/prova_311_510/octave-5.1.0-2.x86_64/build/test/mex 
/cygdrive/d/cyg_pub/devel/octave/prova_311_510/octave-5.1.0-2.x86_64/src/octave-5.1.0/test/fntests.m 
/cygdrive/d/cyg_pub/devel/octave/prova_311_510/octave-5.1.0-2.x86_64/src/octave-5.1.0/test
make[3]: *** [Makefile:31176: check-local] Error 139


I do not see any new cygwin package released in the last month that I
installed that could cause the simple file tests to fail

%!test
%! f = tempname ();
%! fid = fopen (f, "w+");
%! fprintf (fid, "1\n2\n3\n4\n5\n6");
%! fseek (fid, 0, "bof");
%! c = textscan (fid, "%f %f", 2);   <- here comes the segfault

I also tried the cygwin release 3.1.1 and 2020-01-14 snapshot
in addition to the 3.1.2 to see if something different was
coming with no difference in the outcome.

Now I am seriously thinking about BLODA, but I have not
noted any difference from the two AVs I was using
Antivir and MS Defender, so I am wandering if last
update for W10 Home x64 is the culprit.

Can anyone try to rebuild the Octave package and let me know
if the segfault during test is present or not in your system ?

Be aware that build time is very long (~ 4 hours) and requires
a ton of mathematical libraries.

Any suggestion will be appreciated
Marco