Pip Cet <pipcet@gmail.com> writes:
>
> My guess is 0x7ffeef270000 is your stack's guard page... Can you print
> $rsp to confirm?

Sorry, because of the erratic behaviour of GDB I killed that one. I have a new segfault in the GC. It is a long stack trace, so it could be a stack overflow. And, by the way, I had the two brakpoints set for the assignments to marker->charpos that Eli suggested, but they were not triggered. I have dumped a part of the stack trace below.