bug#73838: 31.0.50; Problems in note_mouse_highlight if -nw

[Gerd Möllmann]

Eli Zaretskii <eliz@gnu.org> writes:

>> From: Gerd Möllmann <gerd.moellmann@gmail.com>
>> Cc: 73838@debbugs.gnu.org
>> Date: Thu, 17 Oct 2024 09:03:13 +0200
>> 
>> Eli Zaretskii <eliz@gnu.org> writes:
>> 
>> > If that's not what you are suggesting, I
>> > wonder what is wrong with the current code that we need to make
>> > changes which are basically half-solutions.  If the problem is access
>> > to unrelated memory, that is easy to fix by just adding enough slack
>> > to tty_output definition, for example.
>> 
>> You mean by making sizeof (struct tty_output) == sizeof (ns_output) in
>> my case, and let it go? Bloodcurdlingly horrible! I don't even want to
>> think about it.
>
> Why is it a problem to add some dummy buffer to a struct? what's so
> horrible about that?  The reason is to let ASAN build run without
> false positives.

Well, for me it's not a false positive. ASAN is absolutely right about
it says. We are accessing memory that's not there because we are
accessing something of the wrong type. Making the memory the memory
appear doesn't change the fact that we are still accessing something as
the wrong type. I find that horrible, sorry :-).

But it doesn't matter. I have what I posted in my branch, so it doesn't
prevent me personally from proceeding.

> Alternatively, cannot you tell ASAN in some way that this code is
> okay?

The docs say clang supports an ottribute for that 

  Disabling Instrumentation with __attribute__((no_sanitize("address")))

Haven'tever used that, though, so I don't know if it works.