Re: Unexec dumping results in "Segmentation fault" on Windows Msys2

[Eli Zaretskii <eliz@gnu.org>]

> From: Nikolay Kudryavtsev <nikolay.kudryavtsev@gmail.com>
> Date: Sat, 3 Apr 2021 23:20:17 +0300
> 
> Hello. Whenever I try to build emacs-27 branch using msys2 
> --with-dumping=unexec I get:
> 
> make[2]: *** [Makefile:296: 
> /d/Emacs/source/repo/lisp/emacs-lisp/macroexp.elc] Segmentation fault
> make[2]: *** Waiting for unfinished jobs....
> make[2]: *** [Makefile:296: 
> /d/Emacs/source/repo/lisp/emacs-lisp/byte-opt.elc] Segmentation fault
> make[2]: *** [Makefile:296: 
> /d/Emacs/source/repo/lisp/emacs-lisp/autoload.elc] Segmentation fault
> make[2]: *** [Makefile:296: 
> /d/Emacs/source/repo/lisp/emacs-lisp/cconv.elc] Segmentation fault
> make[2]: *** [Makefile:296: 
> /d/Emacs/source/repo/lisp/emacs-lisp/bytecomp.elc] Segmentation fault
> 
> This only happens with the repository version. I've tried "make 
> extraclean" and other clean targets, they did not help.
> 
> With the source archive it's different in that Emacs compiles fine, but 
> it immediately crashes silently when you run it. That's actually the 
> other problem I'm trying to debug, since I'm trying to find a way to get 
> Emacs 26 to compile on Msys2 again and I'm observing the same 
> Segmentation faults for any unexec Emacs versions from the repo. So this 
> seems like a problem with some newer Msys2 package.

The only reasonable way of debugging this kind of problems is to run
the crashing command under GDB, and when it crashes look for the
reason(s) using the debugger.  It's impossible to investigate the
problem just by describing the crashes.

> Could not test the master branch since trying to build it results in:

Is this with unexec or with pdumper?  If the latter, I just fixed that
on master.

P.S. Why are you trying to build the unexec version of Emacs?  It is
basically unmaintained, left to bitrot, so you are likely to meet
problems no one is especially interested in fixing.