Re: pvm_execute_or_initialize SEGV with reproducer

[Jose E. Marchesi]

Hi David.

Thanks for reporting.

> The same also occurs with none of the --disables, they serve to simplify
> the backtrace.
>
> (poke) .file ~/playpen/btf/poke-fault/poke-fault.o
> (poke) load elf
> (poke) load "btf-dump.pk"  # note, this also loads btf.pk
> (poke) var elf = Elf64_File @ 0#B
> (poke) var shdr = elf.get_sections_by_name (".BTF") [0]
> (poke) var btf = BTF_Section @ shdr.sh_offset

I took a quick look, and it seems that the exceptions stack is being
overflown.  This is probably a code generator bug: somehow we are not
executing enough `pope' instructions for all the `pushe'.

As far as I can see, we are starting to "leak" elements in the
exceptions stack in:

  (poke) var btf = BTF_Section @ shdr.sh_offset

As soon as I have a little time I will look at all the places where the
compiler is generating pushe/pope pairs and see what is going on..
unless someone beats me to it :)