[erlang-questions] gdb questions (was Segfault in do_allocate_logger_message)

[Roger Lipscombe]

On 21 April 2018 at 21:51, Vince Foley <vincefoley@REDACTED> wrote:
> Side question.. I am trying to use the etp commands to print out the Erlang
> terms
> (https://github.com/erlang/otp/blob/master/erts/etc/unix/etp-commands.in)
>
> I keep getting this error:
> ```
> (gdb) etp *bp
> Cannot access memory at address 0xb974e0
> ```
>
> And this kind of thing:
> ```
> (gdb) etp-processes
> No processes, since system isn't initialized!
> ```
>
> Am I doing something wrong, or is this just not possible with my coredump?

I've found that success with gdb requires:

- An exactly matching beam. I have to keep an appropriate VM around
for debugging core dumps from production.
- An *unstripped* beam loaded into gdb. Deb packages generally have
stripped binaries, which breaks a bunch of debugging scenarios. We
build our Erlang releases with kerl; we have to keep the unstripped
copies around.