> I don't think it's memory corruption.  I suspect the problem is
> related to the different ways cmgoto chooses to get to the specified
> screen coordinates.  If someone on the affected systems could tweak
> cmgoto such that only the direct move is used, i.e. this code:
>
>      p = (dcm == tty->Wcm->cm_habs
>           ? tgoto (dcm, row, col)
>           : tgoto (dcm, col, row));
>      emacs_tputs (tty, p, 1, cmputc);
>      curY (tty) = row, curX (tty) = col;
>
> then perhaps we could see if my suspicions are in the right direction.


Hi Eli,

I just applied this patch trying to solve a different but related
issue (https://www.virtualbox.org/ticket/13687).

I am happy to report that applying this patch completely solved the
redrawing issues I was experiencing!

One option for you to recreate this issue locally seems to be to
install virtual box, config a virtual machine with multiple cores, ssh
into it and rung emacs.

I've put my diff here
(https://github.com/martintrojer/emacs/commit/bdff1ff98d02f4307659c052d0b35a40a36f0706),
and I understand it can't be merged as-is hopefully this can help you
find a solution that go into mainline emacs.