bug#41357: 28.0.50; GC may miss to mark calle safe register content

[Paul Eggert]

On 5/17/20 10:28 AM, Eli Zaretskii wrote:
> I'm saying that we've lived with this
> bug for a very long time, so if it is real, it is definitely very-very
> rare.

Yes, it very much has the smell of a GC bug: rare and hard to reproduce, but
deadly when it occurs. I wouldn't be surprised if it's causing the rare and
hard-to-reproduce crashes you reported in Bug#41321. You might try installing
the patch into your copy of emacs-27 and see whether it affects Bug#41321.