Is there a known recent Linux locking bug that affects the OCaml runtime?

[mbacarella]

so new it hasn’t been released yet! It will be in release 4.12.

Whoops!

Well, I can say that updating to 4.11.1 didn’t magically cure this problem.

@xavierleroy

During the discussion of that PR, it was mentioned that Glibc / NPTL uses (or tried to use) Hardware Lock Elision on Intel processors. HLE has a checkered history of not working as intended and being disabled a posteriori by BIOS updates. Could your Broadwell processor be affected?

Interesting, though glibc 2.27 changes the usage of HLE to opted-out by default. (You need to start with a GLIBC_TUNABLES environment variable configured to opt-in, which isn’t being done here)