Re: Help with new Windows 98 crash

[Po Lu]

Eli Zaretskii <eliz@gnu.org> writes:

>> From: Po Lu <luangruo@yahoo.com>
>> Cc: emacs-devel@gnu.org
>> Date: Tue, 06 Dec 2022 09:29:04 +0800
>> 
>> init_bignum must be called before make_initial_frame, because that
>> allocates a bignum in temacs (as set_window_buffer calls
>> bset_display_time and Fcurrent_time, which go through the time
>> arithmetic stuff), before our own allocator has been set up, which ends
>> up in the dumped Emacs, leading to a free of a pointer from the wrong
>> heap once the bignum is garbage collected.
>> 
>> I have installed the change on the Emacs 30 branch because I am not sure
>> it is safe for Emacs 29.  Can you think of a safer fix?
>
> There's nothing unsafe in what you did, but:
>
>   . the call to init_bignum inside the !initialized block should be
>     conditioned on HAVE_UNEXEC

But doesn't it have to come before init_window_once in any case?
Otherwise, the wrong malloc will be used even on pdumper builds.

>   . the call to init_bignum that is a few lines below that, and outside of
>     the !initialized condition should be conditioned using HAVE_UNEXEC and
>     initialized such that we don't invoke this function twice in any case,
>     whether this is during dumping or not and whether this is a pdumper
>     build or not

Okay, that's fine by me.