bug#39962: 27.0.90; Crash in Emacs 27.0.90

[Eli Zaretskii]

> From: Pip Cet <pipcet@gmail.com>
> Date: Wed, 18 Mar 2020 06:17:01 +0000
> Cc: Eli Zaretskii <eliz@gnu.org>, Pieter van Oostrum 
> <pieter-l@vanoostrum.org>, 39962@debbugs.gnu.org
> 
> > Although I haven't been following this in detail, I'd like to suggest 
> > trying a
> > GDB watchpoint to find the bug. Watchpoints have been invaluable to me when 
> > I
> > debug garbage-collector and other memory management issues.
> 
> They are! Unfortunately, they require a predictable address at which
> the corruption happens, and we don't appear to have that.

It would suffice to have a predictable recipe where some variable has
the right value under some conditions: then we could put a watchpoint
using that variable's value from a conditional breakpoint that only
triggers under those conditions.  Unfortunately, it sounds like even
such a predictable recipe is not available.