Subject: Re: bug#23529: Request for fixing randomize_va_space build issues

From: Stefan Kangas <[email-masked]>
Date: Sat, 14 Sep 2019 06:18:43 +0200

Philippe Vaucher <[email-masked]> writes:

> When /proc/sys/kernel/randomize_va_space is 2, emacs fails to build:
>
>     Dumping under the name emacs
>     **************************************************
>     Warning: Your system has a gap between BSS and the
>     heap (20865783 bytes).  This usually means that exec-shield
>     or something similar is in effect.  The dump may
>     fail because of this.  See the section about
>     exec-shield in etc/PROBLEMS for more information.
>     **************************************************
>     /bin/bash: line 7:  8981 Segmentation fault      (core dumped)
> ./temacs --batch --load loadup bootstrap
>     Makefile:815: recipe for target 'bootstrap-emacs' failed
>     make[1]: *** [bootstrap-emacs] Error 1
>     make[1]: Leaving directory '/tmp/emacs/src'

Is this still an issue with Emacs 27.0.50 (current master branch)?

etc/NEWS says:

 ** Emacs now uses a "portable dumper" instead of unexec.
 This improves compatibility with memory allocation on modern systems,
 and in particular better supports the Address Space Layout
 Randomization (ASLR) feature, a security technique used by most modern
 operating systems.

Thanks,
Stefan Kangas