bug#57880: 28.1; Emacs crashes with native compilation on when some antivirus program is running on MS-Windows

[Andrea Corallo]

Ioannis Kappas <ioannis.kappas@gmail.com> writes:

> Hi Eli,
>
> On Fri, Sep 23, 2022 at 6:53 AM Eli Zaretskii <eliz@gnu.org> wrote:
>>
>> > From: Ioannis Kappas <ioannis.kappas@gmail.com>
>> > Date: Thu, 22 Sep 2022 21:46:14 +0100
>> > Cc: akrl@sdf.org, 57880@debbugs.gnu.org
>> >
>> > > > Or could there be an early init option to bypass the native 
>> > > > compilation. This
>> > > > way the users can test the issue with is native comp.
>> > >
>> > > There is one already.
>> >
>> > Are you referring to an option for building form source? I couldn't
>> > find an option
>> > to turn off native compile for the precompiled windows binaries (such as 
>> > those
>> > retrieved from the official ftp site or from msys2 pacman) that can 
>> > configured
>> > to disable native comp.
>>
>> It's native-comp-deferred-compilation: set it to nil.  For a good
>> measure, also set comp-enable-subr-trampolines to nil.  Emacs does
>> this automatically at startup if libgccjit cannot be loaded.
>
> Thanks, it's good to know, I could find any straight references about it
> on the web.
>
>> So you are saying that if someone installs Emacs under C:/Users, that
>> Emacs will not work, regardless of the native-compilation, because it
>> will be unable to load the DLLs which come in the Emacs binary
>> distribution, for example the image libraries?  Then it is strange
>> that we haven't heard about such a major issue with Emacs on Windows
>> until now.
>
> Correct. I can't comment on how widespread that is. I personally stayed with
> the 27 branch until I discovered the surprising cause of the failure.
> I would not have reported it with just a simple hexadecimals backtrace,
> without a single clue what might have been going wrong.
>
>> Thanks, but that doesn't really answer my question, which was about
>> the specific brands of AV software _known_ to do this.  You seem to
>> saying that the answer is 'all of them", but I'm asking what are the
>> brands with which this was actually seen.
>
> Sorry for being a mystic here. It is the AV made by the company who authored
> the article.
>
>>
>> > > > Those precompiled with Emacs are fine in this use case since they are
>> > > > not stored in the Users directory, it's only newly compiled files that
>> > > > exhibit this issue because they store the .eln files in the user dir by
>> > > > default.
>> > >
>> > > This means that the problem will only affect people who have libgccjit
>> > > and GCC/Binutils installed, because otherwise Emacs will be unable to
>> > > compile new *.eln files.  Right?
>> >
>> > Yes, since I understand Emacs won't be able to generate any new .eln files
>> > without access to libgccjit.
>>
>> So then we can tell such people (which are relatively rare) to have
>> their home directory outside of the C:/Users tree.
>
> Or let them know of the alternatives, such as the use of
> startup-redirect-eln-cache
> so that they can direct the new .eln files somewhere else? I don't think 
> people
> would want their .emacs.d  to be located outside of the personal user
> folder. (I am not sure if we are referring to the same subject :)
>
> Thanks!

Hello all,

I'm not sure, is there any action we should take for this bug or should
we close it?

Thanks!

  Andrea