Subject: bug#66744: 30.0.50; Emacs crashes when re-dumping into the same dump file another Emacs instance is using

From: Eli Zaretskii <[email-masked]>
Date: Thu, 26 Oct 2023 18:58:34 +0300

> Cc: [email-masked]
> From: Gerd Möllmann <[email-masked]>
> Date: Thu, 26 Oct 2023 17:45:49 +0200
> 
> The linux man page for mmap says, according to Google,
> 
>   MAP_PRIVATE
>        ...
>       It is unspecified whether changes made to the file
>       after the mmap() call are visible in the mapped region.
> 
> So, if the changes made to the dump file in step 3 are visible in the
> mmaped dump file that Emacs from step 2 uses, that would be a bit
> suboptimal :-).

Emacs on GNU/Linux doesn't use mmap, we stopped doing this many years
ago.

It could be relevant to MS-Windows, which emulates mmap and uses the
relevant code in Emacs.  But Ihor doesn't use MS-Windows, AFAIK.