I'm tracking a segfault in ocaml-ssl caused somewhere between 5.0.0-alpha0 and b828211.
I'm still investigating further (and trying to produce a minimal example), but the segfault seems to originate from a call to caml_raise_with_arg here:
https://github.com/savonet/ocaml-ssl/blob/3799dca10f3db5a36bb3ad5ee3a38035a571acdc/src/ssl_stubs.c#L1462
I've confirmed that my code works with 5.0.0-alpha0, but not with 5.0.0-alpha1.