Re: changed dlopen flags in dynlib.c, gccemacs crash

[Andrea Corallo <akrl@sdf.org>]

Eli Zaretskii <eliz@gnu.org> writes:

>> From: hx <silent2600@gmail.com>
>> Date: Thu, 9 Dec 2021 08:51:03 +0800
>> Cc: emacs-devel <emacs-devel@gnu.org>
>> 
>> remove the directory (28.0.90-xxx) from ~/.emacs.d/eln-cache/,
>> start emacs with -nw -q, it will crash after a few seconds without any operation.
>> after that, it will crash immediately when I start it with the same parameters.
>
> It doesn't crash when I try reproducing it, so something is missing
> from the recipe.  Is this with an unmodified Emacs 28.0.90, or is it
> with your change in dynlib.c?
>
> Anyway, does the patch below help?
>
> Andrea, any better ideas?  I don't understand the reason for the
> crash, as we seem to have defenses against this in Fnative_elisp_load,
> so I'm probably missing something.

Hello all,

I'm no expert on 'dlopen' so I'm not sure about the impact of using
RTLD_GLOBAL.  But should be noted that .eln files do share a number of
symbol names, I'm wondering if this could be somehow problematic when
using RTLD_GLOBAL, that's my suspect here.

  Andrea