Argon2 Threading failure

[andreasknoepfle]

We recently started seeing errors 💣 in out production & staging systems related to argon2_elixir.
All calls that triggered the error we found so far were throwing in Argon2.verify_pass/2.

** (ArgumentError) Threading failure
lib/argon2/base.ex:126 Argon2.Base.handle_error/1

The only thing that we can link to the issue is an update from OTP 28.4.2 to 28.4.3 that happened around the same time, where the error now appeared sporadically. Now with 28.5.0.2 it seems that we get the error near to all the time, but it only seems to be appearing after the system ran for a while (weirdly).

Since the error is related to threading, we also tried setting parallelism to 1, to see if we can fix it temporarily, but this doesn't seem to do the trick.
Is there a chance anything related to changes in OTP are causing issues with argon's threading? Do you have an idea what could be going on?

Interestingly enough, we have never seen the issue appearing on our developer machines (mostly Mac, weather in docker/alpine or just natively) but always only in the relatively restricted cloud environments of our customers.

Thank you already 💚

Cheers
Andi

Details:
argon2_elixir 4.1.3
Elixir 1.20.1
OTP 28.5.0.2
Linux/Alpine (hex.pm base image: https://bob.hex.pm/docker?elixir_version=1.20.1&erlang_version=28.5.0.2&os=alpine&os_version=3.23.4 )

[andreasknoepfle]

Since the error is related to threading, we also tried setting parallelism to 1, to see if we can fix it temporarily, but this doesn't seem to do the trick.

We realised that paralellism is probably encoded in the hash when verifying, to that we likely see this error for the existing old hashes.